Our live Barn Owl stream has now been taken down; our male owlet fledged successfully, but unfortunately his sibling died after she became coated in oil whilst hunting a rat...
If you have any questions for John about the Barn Owls, e-mail email@example.com and John will answer your queries.
Monday, September 10th 2012:
Reflecting On The Highs And Lows Of The Breeding Season
In the last blog entry I described the very unfortunate accident in which the female owlet got covered in oil on Tuesday last, and also the subsequent rescue operation on which we embarked in an attempt to save her (read about the incident and rescue mission in the blog entry for 06/09/12 below). It is with sadness that I now report that despite everyone’s best efforts to nurse her back to health, she died on Friday morning, as a result of ingested too much oil.
Michael O'Clery and I removed her from the nest box last Wednesday morning. After treating her according to the best practise protocol for oiled birds, and after assessing the extent of the damage caused, we decided to take her immediately to a wildlife rehabilitation centre in Kilmallock in Limerick, called Animal Magic (www.animalmagic.ie), which is run by Rosie Cambell and Dennis McCarthy. Initially we were quite hopeful that the female would recover, although based on the extent of the damage to her feathers it looked unlikely that she would be able to survive in the wild over the autumn and winter and would need to be kept in captivity until next spring. Unfortunately, after showing some positive signs of improvement, she then took a turn for the worse on Thrusday night and sadly died the following morning. I would like to express a huge thank you to Rosie and Dennis, who did everything they could to save the female, and undoubtedly she was in the best possible care. Over the past few months they have rehabilitated and successfully released six other Barn Owls, as well as three Long-eared Owls, five Sparrowhawks, eleven Kestrels and five Peregrine Falcons - but unfortunately it wasn't to be such a happy ending for our female.
It is always a difficult decision whether to publically showcase certain aspects of wildlife, such as through live nest cameras, as nature can often be unpredictable and sometimes very cruel to witness. However I think the benefits far outweigh the negatives. It was clear that there was significant affection for both owlets amongst the many viewers and general public around the country, and through such intimate views of their nesting behaviour, it hopefully allowed people to reconnect with nature by sharing the trials and tribulations of this magnificent and elusive bird over their breeding season. It is very sad that the female did not make it, she was certainly quite a character to watch over the past number of weeks, and provided much entertainment. However mortality rates of juvenile Barn Owls can be as high as 80% in their first year, and they face many dangers in their first months after hatching. Although it really was a freak accident that resulted in her death, it demonstrates the vulnerability of our endangered Barn Owl population. Hopefully highlighting this vulnerability and increasing appreciation for Barn Owls and the other amazing wildlife we have in Ireland will ultimately benefit their conservation.
We hope to return to this same pair of adult Barn Owls next year to once again follow their fortunes over the spring and summer, so watch this space! For now however the breeding season has come to an end, the surviving young male owlet has departed the nest site, so we can only wish him well on his journey over the coming months and success with finding a territory of his own. I will keep you posted if we encounter him again.
I must say I was massively taken aback by the level of interest and good will out there for the owlets. Thank you to all who tuned in to follow the progress of the birds over the summer, to the many dedicated followers of the owls and to everyone who contacted Mooney or myself to let us know of various happenings inside the nest box.
Thanks also to Maurice who owns the land on which the nest box is situated. Without his help or co-operation the whole venture would not have been possible. He has a huge passion for the owls (he instantly scrapped his plans to renovate the farm buildings once he realised the owls were in residence!). Maurice unfortunately felt responsible for the incident which occurred with the female owlet (and assisted greatly with the rescue operation), but it really was one of those freak accidents and by allowing us to showcase the owls on his land he has probably done more for Barn Owl conservation in Ireland than anyone else!
Thanks also to the National Parks and Wildlife Service and particularly local ranger Tim O'Donoghue who supported the work. Don Mullane from RTÉ, who gave much of his time to address the various technical issues and whose expertise on such matters was indispensible. Also, last but not least Michael O'Clery who has invested significant energy and countless hours of his spare time to help Barn Owls in Kerry.
If you would like to support the conservation work undertaken by BirdWatch Ireland on Barn Owls and other birds of prey, please support our "On a Wing and a Prayer" Raptor Appeal to raise much needed funds to carry out this vital work.
We hope you will join us again next spring!
John Lusby - BirdWatch Ireland
Thursday, September 6th 2012: Narrow Escape For Female
Apart from a few very miserable nights when we sat watching and worrying about the owls, due to the lack of food being brought to the nest, their long breeding season had all but past without any major problems or dramas. However this all came to an abrupt end two nights ago (04/09/12)! Up until this point both owlets were doing extremely well, flying strongly over the past two weeks, exploring the surrounding area, and in recent nights also starting to learn to hunt for themselves (although the adults are still ensuring they are remaining well fed). The older male has even moved away from the nest box during the day and has found a new roost site nearby.
However on Tuesday evening disaster struck. The female left the nest box in the early evening around 20:00, and when she returned a short time later she was completely covered in what seemed to be a thick layer of oil. Obviously oil is more commonly a problem for seabirds and generally not something that owls come into contact with, but the adventurous nature of this female had clearly landed her in a lot of trouble. After assessing the situation, we now have a fairly good idea of what happened. There was a bucket of oil within the farmyard, a rat had managed to make its way into this container and its struggles obviously caught the attention of our female owl, which was too much for her to resist and she obviously dived in to seize the rat. This may have been her first proper capture attempt, but clearly not a wise choice.
Thankfully she managed to struggle back up to the nest box and into our view. From the trail of oil we were able to retrace her movements, as she clambered across the yard, up the side of an old tractor and made the very improbable leap from there to the ledge of the nest box - quite a mammoth and impressive undertaking given her condition. She was clearly distressed as well as being very bedraggled and pathetic looking, a far cry from her confident and immaculate looks of late. Oil can obviously be detrimental for birds, it mats together the feathers, meaning flying becomes impossible. Birds also cannot keep themselves warm and when they instinctively try to preen, in an effort to rectify the situation, the danger is that they will poison themselves by ingesting the oil.
The female covered in oil and looking very sorry for herself
Black and white – the difference between the male and female is stark
We generally try not to interfere with nature if at all possible - however if the female was left alone in this manner she would had suffered a long and agonising death, so the decision to intervene in this case was an easy one. Michael O'Clery and Irene Kavanagh (who had planned a well deserved day off on the beach) met me at the site yesterday to begin the rescue operation, and Maurice who owns the farm also pitched in to help. Given her inability to fly, the female was very easy to catch, and the long and tedious cleansing process began. We carefully washed her in warm water and detergent, trying to remove the thick layer of oil without damaging any of the fragile feathers ... this took quite a while. At the start she was almost unrecognisable as a Barn Owl, but very slowly some of her normal colour started to emerge. We managed to get a lot of the oil off her wings, but it was so embedded in her body feathers that it was not possible to remove all the oil in one go, and she was starting to chill at this stage also which meant we needed to finish the washing process.
Her movements are restricted and she can now longer fly
Looking in a very bad way...
The body feathers are well matted but thankfully the oil didn't affect her eyes
The washing process begins
Keeping her warm was essential
Unfortunately we weren't able to return her to the nest yesterday, as she would definitely have not have been able to survive. To give her the absolute best chance of survival I brought her to Rosie and Dennis, a couple in Killmallock who manage a wildlife rehabilitation centre called Animal Magic (www.animalmagic.ie). Rosie and Dennis are very experienced with birds of prey and I have previously brought numerous Barn Owls to them, which they have nursed back to health and which have subsequently released back into the wild. The female now stands a good chance of surviving, but will need a lot of attention and it remains to be seen whether she will be able to be returned to the wild in the coming weeks.
Thursday, August 23rd 2012
Female on the wing
I watched as the female made her first flight last Tuesday (21st) night, quite strong and confident for her first leap of faith. She has been very mobile since, and now both owlets are able to travel away from the nest at night, but still regularly return from the darkness and back into view of the camera......particularly when there is the strong possibility of food arriving to the nest!
Last night when I tuned in the "snoring" and "hissing" calls of the two owlets seemed to have reached higher decibel levels than ever before, and the volume was really quite impressive. At one stage I could hear a dog repeatedly barking in the distant background, probably in response to these strange and eerie calls! I observed three prey deliveries while I watched last night, all of which were taken by the male, much to the disgust of the female! The male started feeding on the first prey item (which looked like a Bank Vole) in open view of the female, but quickly realised this was a bad idea and retreated with it into a corner for protection. The next delivery he also successfully grabbed, as the female flew out after the adult to harass it for further food as it beat a hasty retreat into the night. By the time the third delivery arrived the male clearly wasn't in much of a hurry to devour it and wandered around for nearly half an hour with it in his bill, trying to decide where it should be eaten, and hopping from the top of the box to the ledge and regularly going back inside the nest with it.
The male owlet grasps the first prey item of the night with its talons as it starts to feed
After the female shows too much interest in his meal he brings it into a protected corner to feed in peace
The male also receives the second prey item, which is quickly swallowed
By the third delivery his appetite seems to have quelled and the prey is carried around for sometime before being eaten
When I tuned in this morning, both were back in the vicinity of the nest, the female roosting inside the box and the male perched just outside on the ledge (see image below). They are clearly enjoying being in the lime light as the two most famous owls in the country as don't seem at all in a rush to depart from our screens!
The male roosting outside the nest box this morning (23rd August)
Monday, August 20th 2012
The male owlet is now spending a lot of time away from the nest at night, exploring and becoming familiar with the surrounding area. Although he is still getting fed by the adults, he will be instinctively starting to seek out prey for himself. The younger female is just on the verge of her first flight, last night (19th August) she was very close to taking off and this will undoubtedly happen in the coming nights. However, even though she has been forced to remain at the nest box while her older sibling takes off into the night, this doesn't stop her exploring her immediate surroundings with similar interest. On numerous occasions I watched her repeatedly manoeuvre herself, head first into a very tight cavity space between one of the rafters and the roof space of the shed, often having great difficulty emerging again. Check out the image below which show her, without much grace exiting the cavity after somehow managing to twist her body around while concealed in there.
Female just about managing to return from exploring a tight space!
Obviously young birds are naturally inquisitive, but this behaviour will also be very useful to the owlets when they leave the nest. They will have to find a suitable site of their own, where hopefully they themselves will nest next year, and if this is to happen they need to be able to locate roost sites and a potential nest site which is dry, free from disturbance and protected from predators. At this time of year, juvenile's right across the country will be dispersing from their natal sites and investigating likely buildings and trees for suitable roost sites. It is mostly at this time of year that we get reports of birds which maybe do not make the best of choices, and arrive into occupied houses via the chimney or manage to get trapped inside roof spaces. Have a look at some of the photos below, which are typical Barn Owl sites and exactly what birds are seeking out.
Typical Barn Owl Nest Sites
Just thought I would throw in the image below also, both owlets have developed into stunning looking birds....they've come a long way since June.
The male has come a long way over the course of the summer and now resembles an adult if seen from a distance
Friday, August 17th 2012
Still residing at home
Both owlets are still roosting in the nest box during the day, although this probably won't last for much longer, and the older male is now spending increasing amounts of time away from the nest during the night, confidently flying around the surrounding buildings in the farm yard, only occasionally returning to the nest to get fed.
The female still has to take to the wing, and sometimes strikes a forlorn figure standing on top of the nest box by herself while her older sibling is playfully darting around and exploring the world away from the nest. On close inspection you can still see some small remnants of the fluffy down on her body, none of which is now visible on the male. A part from this both owlets are now very similar in appearance, and many people are having trouble differentiating them, which wasn't at all an issue a few weeks ago when the female resembled a large and indistinguishable fluffy football! When you look closely, the much lighter colouration of the male is one of the give aways. The colour image below shows the male on top of the nest box with much paler primary feathers on the wing compared to the female on the landing ledge with darker primaries which have greater barring also.
Both owlets sleeping outside the nest during the day
The birds are now starting to regularly explore outside the nest box during the day, which provides fantastic views in full colour. These may well be some of the last views of the birds together and also may be some of their last interactions with each other. After spending every day of the last two months living with each other in a confined space (plus another month before that as eggs!), once they depart the site they will never encounter each other again. However, as I said in the last blog entry, its impossible to predict just when an owlet will depart the nesting area, and this varies from individual to individual. So this nest camera is not only proving to be entertaining viewing but also provides really useful information on the behaviour of the birds, so we'll just have to wait and see what happens next and learn a little more about the birds in the process.
Female venturing outside the nest during the day
There are still small traces of her fluffy down around her legs
Both birds having a daytime wander
This image is from last night (17/08/12); it’s becoming less common to see them both together at the nest during the night.
Tuesday, August 14th 2012
On the Wing!
It's taken a while, and numerous near attempts, but last night the male eventually made his first proper flight! After hopping energetically around the landing ledge, the top of the nest box and the nearby rafters at the start of the night he finally took the much anticipated plunge. After which he spent most of the night off camera in a different parts of the shed, but could still be heard "snoring" from a distance. However he was well able to fly back to the nest box, as he did on a few occasions throughout the night, and he returned to the nest box to roost, resuming the same position next to the younger female that he has occupied for the past two months.
The female is not far behind him, although not quite able for full flight yet. She struck a lonesome figure as she sat on top of the nest box last night, obviously watching the antics of the older male flying awkwardly around the shed, but not able to join him just yet. Just after midnight one of the adults returned to the nest box with food (which was the third delivery of the night) as the female was sitting on top of the box, instead of bringing the prey directly to her, the adult sat on the ledge with it enticing her forward and then flew away, this was repeated a second and third time until the mouse was eventually given to the female owlet.
The female spends most of the night on top of the box as the male is now mobile
An adult uses prey to entice the younger female to venture away from the nest
After three such visits by the adult the prey is finally given to the female owlet
An empty box.........both owlets now spend most of the night outside the nest
At this stage of the owlets development, such behaviour (enticing the owlets away from the nest) by the adults is not uncommon as they encourage the owlets to take to the wing. It is likely that the adult female will also begin to help the owlets learn to hunt over the coming nights. I have only witnessed this myself on a few occasions, but there are plenty of reports from the UK of such "training exercises" as in some areas of the UK the birds become active during daylight and are therefore much easier to observe compared to here in Ireland where they are generally strictly nocturnal. The female will start to circle above the nest with food, snoring loudly, and once she has the attention of the owlets she will drop the food over open ground. The young then eagerly descend on the food item, thus learning the skills involved in catching live prey. The first successful prey capture of the owlets should occur next week, at which point they will generally emit their first proper screech.
Monday, August 13th 2012
When to leave the safety of the nest?
The male owlet, which is the older of the two is now approximately 64 days old, and is now sufficiently developed to fly quite well for short distances. However the stage at which owlets make their first flight attempt can vary between individual birds, and the male as yet has been unwilling to take to the wing until he is assured his wings will serve their purpose! His confidence is growing however and he now spends a lot of time jumping up on top of the box, flapping strongly and almost taking off, so his first proper flight should be imminent.
The male spends a lot of time practising flying, he will take off properly one of these nights...
The male almost taking off from the top of the nest box
There can also be significant variation in the timing of departure the natal site. The literature on this aspect states that by the age of 67 days owlets are fully fledged and usually leaves the nest permanently at this point. Indeed we have had juveniles travel long distances from their natal site very soon after fledging, such as an owlet which hatched in a nest in West Kerry last year and which was subsequently found in Templemore in Tipperary less than two weeks after it would have fledged. However, at other nests we have observed owlets to remain at the nesting area for much longer, and even though they might roost away from the nest itself they can still be heard calling for food from the adults. Its difficult to predict when the two owlets in Tralee might depart the nest site and start to disperse, but for now the small matter of mastering flight still looms for them!
If you look closely at the two owlets you will see a small metal ring on the right leg of each. These were fitted a few weeks ago (under licence from the National Parks and Wildlife Service) and each has a unique code which allows us to identify individuals. Therefore if we come across the two owlets again at any stage over the next few years we will have information on their life history, movements, age etc. As I previously mentioned both owlets could literally end up anywhere in the country, as long as they can survive the first few weeks after they gain their independence.
As well as ringing the owlets, visiting the nests also give us vital insights on the breeding success of pairs right across the country, and every year we monitor 100 or more nests to obtain this information. I previously highlighted a link to a clip on our Duhallow Raptor Conservation Blog (one of our specific raptor projects in Cork and Kerry) which shows a typical Barn Owl nest visit http://www.duhallow.blogspot.ie/2012/07/time-and-effort.html (click on video to play). This is the type of fieldwork we undertake during the spring and summer to learn more about how the population is faring, however it must be noted that this work can only be carried out under special licence and that Barn Owl nests should never be interferred with under other circumstances. Here are some more links to clips of nest visits and ringing Barn Owls to give you an idea of whats involved with this work http://www.duhallow.blogspot.ie/2012/07/three-tree-chicks.html & http://www.duhallow.blogspot.ie/2012/04/video-of-ringing-barn-owl-chicks.html
Here's some images below of the owlets across the weekend.
The male owlet just about to consume a Bank Vole
Both owlets now spend most of the night outside the nest box
Waiting anxiously for food to arrive
Friday, August 10th 2012
Early feast for owlets
Two nights ago I noted that there had been no deliveries to the nest before 01:00 (although viewers from as far flung as Chicago and Perth were able to inform us that the parents did arrive with food in the early hours of the morning). Thankfully last night things were totally different, and the parents were back on the top form once again, with no less than six deliveries before midnight! The first food drop arrived just before 23:00, when both owlets were outside on the ledge, conveniently positioned right next to the microphone.......for a brief period it sounded like the decimal levels from their feverish hissing reached a volume not far off that inside the arena for Katie Taylors fight yesterday. The male managed to jostle his way into position to receive this first delivery and then quickly retreated with it inside the box to protect it from his younger sibling. She quickly followed him, but was soon distracted when another delivery arrived seven minutes later, which she made absolutely sure was destined for her. A little later in the night, within the nest box there was one uneaten mouse left to one side, while the female fed contentedly on a Rat and the male consumed another mouse, a big change from the previous night.
Female with partially eaten Rat, while male is busy consuming a mouse
Female starts to swallow Rat
Still swallowing Rat.........
It has been speculated that the adults sometimes call to the chicks while flying back to the nest, to notify the owlets of their imminent arrival with prey. Last night I watched the owlets all of a sudden get very excited and focus intensely on the "magic food hatch" which is the nest box entrance. Well over a minute then passed before an adult appeared with food, so its possible that this is a situation where the adult called to the chicks, possibly from some distance away as it made its way back to the nest - however these calls would not be possible for us to hear over the microphone obviously.
Check out the images below of the adults - difficult to capture a decent still image due to the speed with which they arrive and quickly depart the nest site.
One of the adults arrives back at the nest, this is most likely the female
One of the adults takes flight after a lightning fast prey delivery
Thursday, August 9th 2012
Both owlets thinking outside the box
Last night was the first time i've witnessed both owlets outside the nest box together. The male is now getting very adventurous and spent a lot of time on the roof of the nest box and even moving along the beams out of view of the camera on occasion. He will make his first, short, albeit clumsy flight very soon! The younger female, who has still a lot of down on her body, seems content to watch the antics of her brother from the relative safety of the landing ledge for the time being. Last night she directed her curiosity towards the camera equipment, firstly flying right into the interior camera, then when she did eventually make it out onto the landing ledge (after crashing about the box for some time) she started to peck and hiss straight into the microphone which made for loud listening!
Undoubtedly the owlets would have been more active as the night progressed had they been fed in the early part of the night. However I watched until 01:00 and there had been no sign of either adult returning with food at that stage. The patterns of the parent’s deliveries are very bizarre at this particular nest, the previous night there were two deliveries before 23:00, which is what is expected. To have no deliveries before 01:00 on a night when the weather was reasonably good for hunting isn't at all typical. In general the number of deliveries to this nest is lower than I have previously observed at other sites where I have used similar nest cameras. However in saying this, a lot of the prey deliveries (when they do arrive) to this nest are large Rats which have a significantly greater biomass than other small mammal prey such as Bank Voles, Wood Mice or Shrews which are the most common items brought to many of the other nests. I did get an email from an interested viewer in Chicago who has been keeping regular tabs on the owlets (without losing too much sleep either given the time difference) and she did see one delivery at 05:25 this morning, which was a mouse which was quickly swallowed by the female. However it seems the recent trend with this blog has been that I comment on the low number of deliveries by the adults and then they proceed to prove me wrong by putting in a good performance the very next night! So hopefully tonight will follow that same trend. We want the owlets to stay in the best health possible before leaving the nest in order to give them the best chance of survival over the coming days, weeks and months........as I mentioned previously mortality rates for juvenile birds in their first year can be as high as 80%!
Also check out the image below which was captured yesterday by Don - who provides all the technical know how for the whole operation.
Wednesday, August 8th 2012:
Owlets Discover Life Outside The Nest Box
The development of owlets has been amazing to watch over the past two weeks since the camera has been in place, and the spectacular looking and lively birds we now see are a very far cry from the helpless, almost reptilian looking chicks that I first witnessed back in late June not long after they had hatched. Both are now active a lot of the time throughout the day and night, preening, flapping or imaginary hunting, instinctively honing behaviour and skills that will be essential to their survival in the very near future. Inevitably they have started to hop out onto the outside landing ledge on a regular basis, and in recent days, particularly the older male has spent much of his nights there. The male has yet to make his first proper flight attempt, but this should happen very soon as his confidence with his wings grows, so watch this space! We are delighted also that the two camera system is now working really well and thanks once again to Don from the RTÉ Limerick studio who was able to set this up. When I was watching last night the views of the male on the landing ledge were fantastic, check out some of the still images from the exterior camera from last night below.
The male sits on the landing ledge, he now occupies this position for long periods of the night
The female also wants to find out what all the fuss is about, this is one of her first glimpses outside the nest box
The male is almost fully grown now and is easy to mistake for an adult
His overly exaggerated head movements and bobbing give the game away that he is a young bird however
The male spends a lot of time stretching his wings and flapping, he should be ready to take the plunge this week!
For the most part the owlets are still getting fed inside the nest box, and last night I watched three deliveries before midnight. Even if the owlets are outside the next box it is usual for the adult male to fly past them with food and bring it and leave it inside the empty nest, almost working on pure instinct, whereas the female will bring the food directly to the hungry mouths even if they are away from the nest.
The male feeds on a Rat which was delivered at 22:10 last night
The female starts to swallow the second delivery at 22:25
Second blog entry, August 8th 2012:
Nestboxes - One Of The Best Ways To Help Owls
Since the nest camera was launched two weeks ago and the two owlets quickly proceeded to win the affections of so many people throughout the country (as well as many people outside of Ireland), there have been many queries about the best ways of helping to conserve Barn Owls in Ireland. Well, definitely one of the best means to do so if you own or have access to suitable land, is to install a nest box, similar to the box in which the owlets currently reside (although not for much longer!). Special Barn Owl nesting boxes are a great way of encouraging birds into an area which might not have other nesting opportunities. As well as providing safe and secure nesting sites, the boxes also allow us, through the Raptor Conservation Project to monitor the birds, thus learning the necessary information about their ecology and behaviour which is required to effectively conserve the population.
There are a various designs for different types of nest boxes, but as long as they meet certain basic criteria, namely being sufficiently deep and spacious and having a suitable landing ledge then they will be suitable from the owls point of view. Check out the different nest boxes below, all of which have been taken up by Barn Owls in recent years. A nest box can be very straightforward to construct, for further details visit one of our project blogs which has useful information on the design and siting of boxes http://www.duhallow.blogspot.ie/p/nest-boxes.html or if you require specific information on how to build a box, whether or not your area might be suitable for a box and where best to install it, then feel free to contact BirdWatch Ireland and we will happily advise you. Bear in mind however that because Barn Owls are very rare in Ireland, there are no garauntees that your nest box will be occupied! Even if something does move into the box, theres no garauntees that it will be a Barn Owl! We have also had a range of other birds and animals from Kestrels, Jackdaws, Stock Doves, Squirrels and even Pine Marten take up residence!
Luxury Barn Owl Box! Photo by Hugh O'Donnell
'A' Frame style nestbox; photo by John Lusby
Nestbox in barn; photo by John Lusby
This Barn Owl nestbox is a pole box! Photo by John Lusby
'A' Frame style nestbox
Sunday, August 5th 2012:
Owlets still to make the big leap
Viewers who tuned in on Friday evening and throughout Friday night, might have assumed the owlets were being uncharacteristically quiet, however this was not the case as there were some technical issues with the microphone located close to the nest box. This was rectified by Don from RTÉ yesterday and were pleased to report that the sound is now working perfectly again. It’s just not the same watching the owlets at night without listening to their continuous "snoring" and "hissing" calls.
Don also installed a two camera system which is now currently in operation. There is now an exterior camera which works on a motion sensor, so every time the motion sensor is triggered (hopefully more so by owls as opposed to moths) it will switch to this camera. The idea behind this is that once the chicks start to explore outside the nest box, the exterior camera will be able to register their movements.
Given the isolated location of the nest box the entire set-up required to transmit the live feed is quite complex, check out the all the high-tech gadgets which look very out of place inside a very old tractor which hasn't budged in many, many years. This tractor has been there for as long as the owls, as once they moved in the farmer didn't want to move it in case it would disturb the birds. He jokes that every year the owls however do him the favour of painting the tractor for him, as its parked just below a perch regularly used by the birds and inevitably ends up covered in "white-wash" splashings after a busy breeding season.
Nestwatch 2012 Control Centre!
Old meets new...
Equipment inside the tractor
The owlets themselves were oblivious to any technical glitches and everything has been going very well with them both over the past two days. On Friday night there were five prey deliveries before midnight, which is exactly what should be happening at this stage. Last night things were a little quieter, with only two deliveries before 01:00. The prey item brought to the nest at 00:15 last night was a bird; this is the second time I've observed a bird being brought to this nest, showing that although small mammals dominate the diet, the owls will also take other prey, and as well as birds they will also take frogs and on rare occasions bats will also feature.
Delivery by the adult male on 04/05/12; he comes right into the nestbox with the prey on this occasion
Older male with mouse on 04/08/12
It is interesting that I haven't seen any Pygmy Shrews being brought to the nest as of yet (very easy to identify due to their tiny size), even though owls do feed a lot on these shrews. The reason behind this is that if one of the adults catch a Pygmy Shrew while they are out hunting, it is likely that they decide that the energy required to fly all the way back to the nest with such a small prey item isn't worth it, consume it themselves and the continue to hunt for larger prey for the chicks. For this reason the diet of the adults and the chicks in the nest can be quite different at this time of year.
The older male owlet is now approximately 55 days. Even though he was making his first attempts at leaving the nest box a few days ago, his desire seems to have waned somewhat recently. At this age he should be able to make very short, albeit clumsy flights and it is expected that he will make it out onto the landing ledge very soon. Even his younger sister was trying get out the entrance last night, however she still has quite a bit of down to lose before she can make an effective first flight attempt, her confidence levels seem just right though!
Female attempts to get out the entrance hole
The older male has shed the majority of his down at this stage
Female flapping furiously and jumping around the nest
More impressive head contorting!
When I had a look this morning, the female was leaping around the box, pouncing on imaginary prey, bumping into her stationary older brother on a regular basis. Still a lot to learn before they try this on real live rodents!
Friday, August 3rd 2012: Early Start For Adults
In yesterday's blog entry, I commented on how the initial prey delivery to this nest is generally much later than would be expected, and more delayed than we have witnessed at other nests elsewhere in the country recently, even those located very close to this nest box. Well both adults must have picked up on these comments, and then took it upon themselves to prove me wrong! Last night, not long after dark, there were two deliveries back-to-back, the first of which was at 22:17, followed swiftly by another just over a minute later at 22:19.
Second delivery at 22:19, a Wood Mouse is given to the female, while the male is already busy feeding on the first delivery
The male swallows the initial prey delivery
There were then another three deliveries before 01:00, and hopefully more arrived after I finished watching at this point. So, another good night for the owlets!
Given the short time period between the first two deliveries, it is obvious that this was both the adult male and female delivering to the nest. In general the male does the majority of the hunting across the breeding season and is likely to be providing most of the prey to the chicks at this stage. However it is difficult to tell the sexes apart based on the brief glimpse we get of the adults as they deliver to the nest and then quickly fly off into the night to resume hunting. If we manage to deploy the motion sensor and exterior camera later today, then we should be able to get better views of the adults and may well be able to distinguish between them based on their plumage characteristics.
Males are usually paler than females, with the white breast often extending up around the neck as a broad white collar. Females generally have a greater degree of dark, diamond shaped flecks on their under-body and under-wings, but this can be very difficult to see in the normal senario that you would observe a Barn Owl (at distance and in darkness!). The photo below shows an adult male on the left in comparison to an adult female on the right, from which some of these differences can be seen.
Adult male and female Barn Owls
The older male owlet, which is now approximately 53 days old is still growing but is not far from being fully developed and should be attempting his first flights across the weekend or early next week. You can see from the image below, which was taken last night, that he has very little fluffy down left around his head and that the characteristic heart-shaped facial disc is now well formed.
The male now has the appearance of an adult bird
Male stretching his wings, his feathers are still growing and will be fully formed in about 12 days
His younger sibling still has quite a bit of down to loose, however such age differences is normal between owlets, as shown from the photo below of two owlets from the same brood in Roscommon which look markedly different.
Two owlets from Roscommon
Thursday, August 2nd 2012: Adults Return To Form
Thankfully last night was significantly better in terms of the hunting performance of the adults compared to the previous night. The first delivery to the nest was quite late, however a late start now seems to be customary with this particular pair, which take longer to return to the nest in the early part of the night compared with other pairs we are monitoring.
At 23:20 one of the adults brought a large rat, which was quickly snatched by the female, and after some minor squabbles with her sibling she managed to maintain rights over this first delivery, quickly remove its head and then swallow the body whole.
First delivery at 23:20; female starts to consume a large rat
She swallows the rat whole, as the tail still hangs out from her mouth!
A second rat was delivered at 00:12 which was consumed by the male, who was obviously very hungry and eager to get his share at this point.
Second delivery at 00:12; another large rat, almost as big as the male
Once they are fed they can relax again!
At 00:44 yet another large rat was dropped at the nest and taken by the female owlet.
Third delivery at 00:44; this rat is brought with head intact but its quickly removed by the female owlet
Just before I finished watching at 01:30 there were two further deliveries at 01:21 and 01:23. One of these was a Bank Vole, the other, due to the speed at which it was delivered and grabbed by the chicks was difficult to identify, but was either a vole or a mouse.
Fifth delivery at 01:24; a Bank Vole which is given to the male
Therefore five deliveries in total before 01:30, which was fantastic to see after the worrying lack of prey the previous night. When I tuned in this morning at around 08:00 there was an excess of prey in the nest, indicating the chicks are currently satisfied and well feed. Owls however have very little fat reserves, as they need to keep a light body weight in order to be effective aerial hunters and because of this they need to feed every 24 hours.
Some serious head contorting
When you tune in to the nest camera in the morning time, the calls of Jackdaws from just outside the nest box can quite obvious. Barn Owls and Jackdaws have a very interesting relationship in Ireland. The Irish Jackdaw population is substantial, and their numbers are comparatively much higher here than the UK and other parts of Europe. They tend to occupy the same nesting sites as Barn Owls, such as ruined buildings. In some castles and ruined mansions, literally every available cavity can be filled with sticks by nesting Jackdaws in the spring and early summer.
Typical Barn Owl chimney nest which is on top of an old Jackdaw nest
For Barn Owls, Jackdaws are both a blessing and a curse. I have witnessed numerous violent exchanges between both species. Jackdaws will aggressively mob a Barn Owl which emerges from its nest or roost while they are still active, and I have seen Jackdaws try to build their nest in a cavity or chimney which is already taken by an owl. On a few occasions they have even been successful in ousting the owls from a nest site. More often it goes the opposite way however; a pair of Jackdaws which made repeated attempts at building a nest within the same chimney as a pair of owls in County Offaly obviously exceeded the threshold of what the male could tolerate, and both were clinically dispatched by the male.
I have also watched a male owl fly maliciously to several cavities where Jackdaws were nesting in a castle in South Tipperary and proceed to launch an aggressive attack, safe in the knowledge that he had the upper hand in the darkness. The high pitched screams of the Jackdaws were almost deafening! As well as being the foe, Jackdaws are also a necessary friend to the Barn Owl however. Within ruined buildings, a significant number of the Barn Owl nests which we monitor every year are actually on top of old Jackdaw nests.
Because Barn Owls don't build a nest of their own, chimneys which aren't blocked are unsuitable for them to nest in, and therefore they rely on Jackdaws to first block a chimney or other cavity with sticks and nest material before they themselves can use the particular site. So without Jackdaws the availability of suitable nesting sites throughout the countryside for owls would be significantly limited.
Wednesday, August 1st 2012:
Heavy Rain Means Hungry Owlets
The male stretches his wing’s, he’s not far off his first flight attempt
The primary feathers are still growing but will soon be fully developed
Both owlets followed the movements of a fly with intense interest
A total of 32mm of rain fall was recorded at Valentia yesterday. I spent most of the day in Kerry visiting other Barn Owl sites alongside Michael O'Clery, and soaked to the skin would be a massive understatement! Unfortunately this windy and very wet weather continued around the Tralee area well into the night. I watched the owlets from 22:00 until 00:30, this is the period when you would expect the majority of activity in terms of prey deliveries. For example, at a nest site I visited in Cavan last week, on a calm night I watched five deliveries to the nest before 23:00. Last night however there were no prey deliveries before 00:30, which is quite concerning. I had to tune out at 00:30, so if any viewers have news of how the owlets fared after this time, or observed the adults returning to the nest with food after this point, please contact me via email.
Barn Owls are not well adapted to hunting in periods of prolonged wet weather (basically our summer!). They have very soft plumage, which is poorly oiled in comparison to other birds and as a result can become easily saturated. The continuous rain last night would have undoubtedly affected the hunting success of the adults. In general it has been a very poor nesting season for Barn Owls, and it can be safely assumed that the weather conditions have at the very least played a part in this. Almost half of the pairs we have monitored across the country have failed this year, in comparison to last year when over 90% of pairs fledged chicks.
Prey stash within a Barn Owl nest: From left to right:
4 Greater White-toothed Shrews, 1 Bank Vole & 2 Wood Mice
When hunting conditions are optimal, Barn Owls can bring prey which is greatly in excess of the amount the chicks require. In a good breeding season it is common to find a stash of untouched prey items in a nest beside a brood of well feed chicks, such as the small mammal prey shown below which I found in a nest with two chicks in South Tipperary. Unfortunately, there is currently no excess of prey within the nest box in Kerry. Hopefully the situation (both the weather and the prey deliveries) will improve tonight.
Adults Eventually Arrive With Prey
After our request for information on prey deliveries after 00:30 last night, we have received a number of reports from people who were watching the owlets late at night. It seems there were two prey deliveries between 02:00 - 03:00 last night ... eventually! Hopefully there were additional visits from the adults with food after 03:00, as the prey requirements of the chicks at this stage would be much greater than a single small mammal each. One of our listeners, Eilish Moloney from Limerick, who was keeping an eye on the owlets last night, also commented on further attempts by the older male to make his way out to the landing ledge, unsuccessful as yet, but getting closer all the time.
Given the fact the chicks will soon be exploring outside the nest, we're currently looking at the possibilities of deploying a two-camera system (thanks to Don the technical genius). We have installed a second camera outside the nest box and we're currently working on incorporating a motion sensor so that activity on the ledge will be picked up by this exterior camera. This would allow fantastic views of the adults bringing food to the nest, as well as the initial flights of the chicks.
At 14:30 this afternoon both chicks were alert and lively, both heads bobbing in perfect symetry as they meticulously followed the movements of a fly within the nest.
Tuesday, July 31st 2012
Before I had a chance to tune in myself last night, I got a flurry of phone calls and emails at around 21:30 to notify me that the male had made his first attempt to view life outside the nest box, as he had apparently hopped up to the entrance briefly before tumbling back down to the base of the box. After this attempt it seemed he was hidden from view for some time, eclispsed by his much rounder, younger sibling! Many people feared he had fallen out from the entrance... until, much to their relief, he re-appeared from behind his sister.
What's going through his mind? The male owlet eyes up the entrance with increasing enthusiam...
Falling from the nest can however be a problem for Barn Owl chicks at this stage of their development, and to reduce the risk of this happening we always install a landing ledge in front of the entrance hole. The older male is obviously getting a strong urge to start exploring and practising with his wings outside the nest box and undoubtedly there will be further and more successful attempts to get out to the landing ledge in the coming nights. We hope to switch to an exterior camera for these exciting first flights!
The male owlet stretches his wings ... it’s getting tight in there!
Last night there were two prey deliveries before midnight, the first was a vole which was brought in at 23:13. This was eagerly snapped up by the female, after which she hurridly shuffled into the corner of the box to mantle her meal and protect it from the male, which is typical owlet behaviour.
The first food delivery last night was at 23:13
The second prey delivery was a large rat which was given to the older chick. The rat was delivered with the head intact - however it is very common for the adults to decapitate rats before they bringing them to the nest, which makes sense as it reduces the weight the birds have to carry back to the nest. The male owlet managed to do the decapation himself, before swallowing the rest of the body whole.
The second prey delivery, at 23:23, was a large rat
The number of rats being brought to the nest by the adults is quite a surprise, as these are by far the most important prey item over the past week. Rats, due to their large size obviously provide a substantial portion of the chicks required prey intake, however the concern of secondary poisoning from rodenticides always emerges when birds feed to a large extent on rats.
Some communal preening!
Click here to view details of the Duhallow Raptor Conservation Project, including a video of John Lusby making his way through a derelict building to reach a Barn Owl nest site...
Monday, July 30th 2012
Ireland's two most famous owlets continued to progress well over the weekend, as thankfully the weather provided perfect hunting conditions for their parents. Rats definitely dominated the menu over the weekend, with some impressively large prey deliveries, alongside Wood Mice, Bank Voles and a bird.
The oldest male is now approximately 48 days old and there are only small remants of his fluffy down remaining; last night he spent a long time eyeing up the entrance of the nest box with increasing interest, and hopefully in a few days from now he will start to make his first explorations outside the nest. However, before he starts to leave the nest, we're hoping he will gain some additional weight, as at present his size pales in comparison to his younger sister, who is looking and behaving exactly like a young and healthy owlet with an insatiable appettite should at this age. As is always the case with owlets, true characters start to emerge at this stage of their development and this is most certainly the case with our two chicks. The older male is the quiter and behaves in a more passive manner of the two, while the younger female is most definitely the dominant force in the nest, best displayed up at around 1am last night when she devoured a large rat whole and then immediately waddled back to the front of the nest box and continued calling for more food! There was at least eight prey deliveries last night.
Over the past few days, we've noticed that the owlets tend to sleep standing on one leg. But why do they do this? Tune in tomorrow, Tuesday July 31st, to hear John Lusby's fascinating explanation!
Screenshots From Nestwatch 2012: Barn Owls
Click here to view the Barn Owls in Nestwatch 2012, and to read detailed notes about Barn Owls and the Nestwatch 2012 project...
About the Author, John Lusby
John Lusby with a Barn Owl chick; photo by Alex Copland
John Lusby is Raptor Conservation Officer with BirdWatch Ireland. He established and co-ordinates the various aspects of the Raptor Conservation Project including research, monitoring, policy and awareness for raptors, and is one of the leading experts on birds of prey in Ireland. He has extensive field experience on the range of raptors which occur in Ireland, particularly Kestrel, Long-eared Owl and Merlin, but has focused most attention on his work on Barn Owls which he initiated in 2006. Since this time he has developed a unique and intimate understanding of the Barn Owl in Ireland through countless hours in the field and through detailed research on the species, which he has made accessible to birdwatchers, landowners and the general public in order to benefit the endangered population. He has used numerous techniques such as radio telemetry, dietary analysis, toxicology analysis and nest camera technology as well as detailed annual monitoring of over 100 nests to learn about the ecology and requirements of the species. This work has been well received in the scientific community both within Ireland and internationally. One of his many memorable “owling” experiences occurred when a female flew from a nest which he was watching at dusk, landed on his knee and started to preen while he sat in motionless shock!
John Lusby, Raptor Conservation Officer, BirdWatch Ireland.