ABI group attend Barn Owl ringing

The Acquired Brain Injury (ABI) group from Castleisland attended the ringing of two Barn Owl chicks at a site in Co. Kerry recently. The ABI group built a series of nest boxes for our Barn Owl and Kestrel projects (you can see that post on this page HERE).

 Members of ABI Ireland, with the landowners and their families, at the Barn Owl ringing, July 2013 (M.O'Clery).

Brin McDonald (Duhallow Birdwtching Club) and Maura Walsh (CEO at IRD Duhallow) with one of the younger enthusiasts, at the Barn Owl ringing, July 2013 (M.O'Clery).

Chimney nest box chicks ringed

The Barn Owl chicks which featured in recent posts were ringed this week. They were about 50 days old, not quite fully grown. They would be due to fledge around the second week of August and as such, are the earliest Barn Owl chicks in our study area so far this season

Barn Owl chicks ringed at the chimney nest box site in Co. Kerry, July 2013 (Filmed under licence: M.O'Clery and J.Lusby).

The previous recent posts which featured this site can be seen on this page HERE, and HERE

Recent Barn Owl ringing results

The following resulted form two days of ringing of Barn Owl chicks this week at known nest sites in Kerry.

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Nest box site, Dingle Peninsula – No birds present.

Nest box site, Dingle Peninsula – 1 chick ringed.

Old farmhouse, Dingle Peninsula – 1 adult female ringed. No chicks.

Derelict cottage near Castlemaine – 1 of 3 chicks ringed.

Derelict church near Castlemaine – No birds present.

Quarry, east Kerry – 1 adult present. No chicks

Chimney nest box, east Kerry – 2 chicks ringed.

Castle, Kerry – 2 chicks ringed.

Old cottage near Castleisland – 1 adult present. No chicks

Old farm buildings near Castleisland – 2 adults present, no chicks.

So, ten sites which so far have produced eight chicks. Well below average. Worryingly, two traditional sites seemingly had no birds present.

Quarry site in Kerry where Barn Owls are present in a small tunnel in the rock face. An adult was seen here, but it is possible that young were undetected further along the rock shaft, so a watch at dusk is still needed here to determine if there is any young here (Photo: M.O'Clery).

Two chicks fledged from this site last year, but this year only one of the adults were present and no chicks. The nest was in the chimney, though the adult was roosting in the tiny roofspace on the left of the building, accessed through a single missing slate (Photo: M.O'Clery).

Barn Owl chick, or fluffy toy?

Barn Owl chick, Co. Kerry, 24th July 2013 (M.O'Clery).

If cuteness was an Olympic sport, this Barn Owl chick would win gold...

Barn Owl chick, Co. Kerry, 24th July 2013 (Filmed under licence: M.O'Clery).

This chick is about 20 days old, just old enough to regulate its own body temperature. The nest was in an old cottage in east Kerry, and is one of the few broods of three we have seen so far this summer.

The Barn Owl Survey in action

This video shows an examination of a known Barn Owl site in Co. Kerry. There have been signs of the birds presence in this old farmhouse each year since the site was discovered in 2008, but the owls have not yet bred here. Two nest boxes have been placed inside the house, the site is very isolated and rarely visited, and there is ideal hunting habitat nearby, so it is absolutely perfect for Barn Owls.

Every known site in Duhallow and Kerry is checked by us at least once each season. It can take a number of years for a site to be occupied, in some case four years or more, and at others, seemingly suitable sites have never been occupied, but in one notable case, Barn Owls occupied and nested in an Owl nest box within just a few weeks of its installation.

Let's have a look and see what's going on here...

How long does a Barn Owl live?

Two year old female Barn Owl, Co. Kerry, 24th July 2013 (M.O'Clery).

Barn Owls are generally short lived birds, and since ringing of Barn Owls began in Ireland in 2008 only a handful of birds ever caught and ringed have been three or more years old. This is a two year old, a female, which was trapped at the same site as last year, an old mansion in Kerry in July 2012 (you can see an account of that on this page HERE)

Barn Owls which are kept in captivity regularly live to be 15 or even 20 years old, but they obviously don't face the same hazards as a bird in the wild. In Ireland, our studies show that at least half of all birds which fledge from the nest will not make it to their first birthday, and it is rare indeed to find a five year old bird. There are a number of sites which we know have been occupied by Barn Owls for 20 or more years, but this does not mean it is the same individual owls in residence, rather there has been a whole series of replacements over the years.

Barn Owl attacked by Sparrowhawk

While conducting an evening watch on a Barn Owl nest box site on Friday a most unusual event was witnessed by Michael O'Clery...

The scene of the action – the nest box on the chimney, the telegraph pole and the grey roof of the barn behind (Photo: M.O'Clery).

"From my position, hidden by the field edge, I could watch one of our nest boxes, on top of a chimney in Co. Kerry. As dusk fell, an adult Barn Owl flew out of its roost in an adjacent barn and landed on a telegraph pole near the nest box. One of the young Barn Owls saw the adult land and came to the entrance of the nest box and started 'snoring' loudly for food. The adult looked toward the box and then started to stare at the rough grass below its high perch.

"Judging by the intensity of the attention, I thought I might see the adult Barn Owl make a kill on some small mammal below, however another movement behind the owl caught my attention. A female Sparrowhawk flew low and fast over the roof of the barn and flew straight at the Barn Owl.

"The owl was oblivious to the approaching danger from behind, but at the very last second turned, saw the Sparrowhawk, and virtually leapt into the air to meet the Sparrowhawk, talons to talons, before flying downward, low and fast into the nearest copse of trees. The Sparrowhawk which had to stall mid-flight, then twisted to make a 180 degree turn to pursue the owl with astonishing acceleration. The initial loss of speed of the Sparrowhawk however seemed to just allow the owl time to make good its escape and the Sparrowhawk pursued the owl to the edge of the treeline before gliding up an over. It seems the owl had a very narrow escape."

Female Sparrowhawk (Photo: Ben Phalin).

Female Sparrowhawk with a freshly killed Magpie (Photo: David J. Coley).

Barn Owls have few predators, and on the continent, Goshawks are the only raptors which have been regularly documented as killing Barn Owls in the wild. However in two studies on mortality of Barn Owls in England, of nearly 300 documented deaths of Barn Owls, three were attributed to Buzzards, and one to a Sparrowhawk.

A female Sparrowhawk will regularly take relatively large prey such as Woodpigeon and Magpie. The weight of an adult Woodpigeon is about 400 grammes, whereas Barn Owls typically weigh in at about 280 to 310 grammes, so it would seem that Barn Owls might well occasionally feature on the Sparrowhawk menu.

Two Barn Owl chicks in one of our nest boxes

Birds of prey in general are suffering one of their worst breeding years yet. We saw in an earlier post how Long-eared Owls suffered an almost complete collapse of breeding attempts with only five chicks produced from 61 sites nationwide. Reports are that Peregrine falcons too have suffered breeding failure with for example only one nest of a sample 19 producing young in Kerry/Cork (and the chicks were robbed from that one). Kestrels failed to breed at most sites, though the ones which did breed fared well.

Barn Owls nest later in the year so we are only now beginning to see how their season is developing and unfortunately, it is not good. Quite a few sites checked so far have been abandoned, and adults are not breeding at others. Nests with chicks are proving the exception this year.

At least here we have a bit of good news – two healthy looking chicks in one of our nest boxes yesterday while checking our Duhallow sites. They are about three weeks old, and none of the flight feathers are yet visible. They should be at the nest for another month and a half, so will be fledging in late August or early September. Working backwards, if they are 21 days old, they must have hatched around the last day of June, which means the eggs were laid around the last days of May, about 4 weeks later than the average date of around 7th May.

Two Barn Owl chicks at a nest box in Duhallow, 19th July 2013 (Filmed under licence: M.O'Clery).

Barn Owl chicks in chimney nest box

Nest box on top of the chimney of an abandoned cottage, Kerry, 17th July 2013, and (inset) a close-up of the box (M.O'Clery).

At last, some good news on Barn Owls. There are at least two chicks in one of our nest boxes in central Kerry. Have a look and listen to the video clip and you can hear the distinctive 'snoring' call of two or more chicks from inside the box.

From the volume of the calls and the brief glimpses of one of the birds taking a peep out of the box, they look to be about 40 to 45 days old, or about two-thirds of the way to fledging.

This site had three young last year and featured on the 'Living the Wildlife' documentary by Colin Stafford Johnston which aired on RTE last April. Thankfully, it has proven the exception so far this season, with most Barn Owl sites visited in our survey so far either  abandoned, or the adults have not bred.

We will be ringing the chicks at this site shortly, so check back for more soon.

In the first part of the clip, the snoring starts quietly as dusk falls (accompanied by singing Whitethroats in the background, formerly a rare summer visitor to Kerry, but making a strong comeback this summer).

In the second part of the clip, later in the evening, keep an eye on the entrance to the box as the snoring intensifies when one of the young spots an adult on a nearby telegraph pole and comes close to the entrance in its eagerness to get some food (filmed under licence: M.O'Clery).

Barn Owls using chimneys

Around half of all known Barn Owl nest sites in Ireland are in chimneys, in disused or derelict houses, castles and mansions. Barn Owls can climb very well, and with the help of strong legs and wings they can scale a vertical stone surface relatively easily. 

Barn Owls often nest in derelict buildings and those types of buildings are a natural source of curiosity to Barn Owls and those trying to survey for Barn Owls. One of the more difficult nests to detect are in buildings where the Owls are actually nesting down the chimney. 

This is one such example and it was only a phone call from a curious neighbour which directed attention to the cottage. The owners had died some years before, but the neighbours were keeping it tidy and unknown to them, Barn Owls had moved in to the central chimney, nesting on top of the sticks of an old Jackdaws nest which had blocked the shaft.

An apparently occupied cottage, but with new tenants nesting in the chimney (Filmed under licence: M.O'Clery).

Here we can see the Barn Owl about eight feet (2.5m) down the chimney shaft. The slow, sideways swaying, partially opened wings and low hissing sound is the threat posture, to make the owl look bigger and more imposing to any potential predator, or Barn Owl surveyor.

Long-eared Owls suffer widespread breeding failure

As the Duhallow Raptor survey for Long-eared Owls winds down for this season, the results are stark. There has been a widespread breeding failure this year with only two chicks fledging from a single nest, from 14 known nest sites.

These results have been replicated elsewhere in the country with the breakdown roughly as follow:

Duhallow 14 sites, 2 chicks at 1 site.
Clare 1 site, no chicks
Connemara 2 sites, no chicks (though 3 eggs were laid in 1)
Dublin 4 sites, 1 chick.
Galway 5 sites, no chicks
Kerry (outside Duhallow) 5 sites, 1 chick.
Mayo 2 sites, no chicks
West Offaly 19 sites, 1 chick.

TOTAL 62 sites, with only 5 chicks at 4 sites.

Empty Long-eared Owl nest.

A perfect breeding site (an old Hooded Crow nest), high in a conifer, in perfect habitat, where a pair of Long-eared Owls have been displaying and holding territory all spring, only for the birds to eventually fall silent and cease their breeding attempt, a pattern repeated at many sites in Duhallow and all over the country (Photo: M.O'Clery).

The cause for the widespread failures are largely unknown, though it may be that the unusually cold spring was a major factor.

Owl paradise

We saw a small slice of owl paradise in an earlier post HERE, where a landowner, sympathetic to wildlife, has allowed some of his meadows near Newmarket to develop, resulting in an abundance of insect, wildflowers and small mammals. Kestrel, Long-eared Owl and Barn Owl all nest within a kilometre of these meadows.

Below, another slice of owl paradise can be seen. This site is in Co. Kerry, and the large fields, normally given over to grazing and silage, were bought by a wealthy landowner who has (for reasons unknown) not cut or grazed the grass in about 5 years. The result is a truly enormous area of habitat, perhaps 1.2km by 800m, unaffected by grazing, fertilizers, pesticides or mowing and it has become a wildlife paradise as a result.

Grassland, Co. Kerry (11th July 2013 (M.O'Clery).

During recent owl survey work, this area was checked and on both occasions, both Long-eared Owl and Barn Owl could be watched hunting over the grassland at dusk. One of the few places and occasions in Ireland where it is possible to see both species simultaneously.

A sure sign

Barn Owl pellets and 'whitewash' (droppings) (M.O'Clery).

This metal shed in a remote area of Co. Kerry has a long history of visits by Barn Owls. The line of white in the picture is under one of the beams in the shed where one or more Barn Owls have roosted. The accumulation of pellets and droppings tells us this site has been used by the owls for a considerable time, possible several years. It is rare indeed to see such an accumulation. There must surely be a nest somewhere nearby...

Peregrine versus Barn Owl

Peregrine Falcons have been doing well in the past decade, following a crash in the population in the 70s due to pesticide poisoning. Their recovery has been complete thankfully and they are now spreading into areas where they have not been known to breed before, particularly at inland sites. They need a cliff ledge on which to nest and quarries, church steeples, castles and other large structures have all been used in areas where no natural cliffs exist.

This castle site in Duhallow has long had Barn Owls present, but a search of the area yesterday also revealed the presence of a Peregrine Falcon. Although no bird was seen, the feathers and pellets were found under a roost site on the outer castle walls.

Moulted feathers and 'whitewash' below the castle walls (M.O'Clery).

Two Peregrine pellets,  containing the remains of birds' bones (bird bones are usually hollow) and feathers, very different from the larger, slightly glossy black pellets of Barn Owls which usually contain the fur and bones of small mammals (M.O'Clery).

Peregrine feathers and pellets, Duhallow (M. O'Clery).

(click on any of the images for a closer look)

Although Peregrines and Barn Owls can share the same site, the arrangement seems to be an uneasy one, and we know of cases in Ireland of Barn Owls disappearing from traditional sites shortly after the Peregrines moved in. Peregrines are a powerful and aggressive species and have little tolerance for other birds of prey near their nest site. In the Barn Owl's favour is the fact that they fly and hunt at night when any Peregrine at the site is tucked away at its roost.

First Barn Owl chicks of the season

The first Barn Owl chicks of this breeding season have been noted, at a known nest site in a castle in Duhallow. Have a listen to the sound on the clip.

Young Barn Owl chicks 'snoring' for food, Duhallow, 8th July 2013 (M.O'Clery).

This was recorded inside the castle late last night - not a place for the faint-hearted, or those with an over-active imagination.

There are at least two chicks, possibly three, and from the relatively weak volume, are probably about three weeks old. This site has produced the earliest broods of young owls in two of the last three seasons in Duhallow and Kerry, but this year are at least 4 weeks later than in any of the previous seasons. We will hopefully be ringing the chicks at this site in the coming weeks.

A rare sight, and a rare sound, this year

Survey work into Long-eared Owls in Duhallow this year is mostly completed, and it has become apparent that it has been a disastrous breeding season for this elusive and little known species. Of 13 sites where Long-eared Owls were present this spring, or nested last summer, none have yet produced any young. This stark figure has been reflected elsewhere in the country and when all nesting areas or active territories studied nationwide are added up, a total of 42 sites have produced only five chicks.

A rare sight - a young Long-eared Owl chick (Adrian Rooney).

We can only surmise that it was the unusually cold spring which accounted for the failed breeding. Long-eared Owls nest relatively early in the season, and the late spring may have suppressed numbers of their main prey small mammals and birds.

There is still hope that some chicks will yet appear at the study sites, and with an extraordinarily good forecast for the next week, a final all-out effort will be made to locate any calling young.

The 'squeaky gate' call is loud and persistant, and can be heard for up to a kilometre on calm  summer nights. If you hear one, please let us know (contact details HERE).

Have a listen. 

The recording(below) is the call of a Long-eared Owl chick, calling for their parents to bring them food. It can be surprisingly loud.

Copyright, David Marques. www.xeno-canto.org. Catalogue no. XC59710

Birds on the menu for hungry Kestrel chicks

Kestrel chicks, Co. Kerry (Filmed under licence: Michael O'Clery).

Two of the four Kestrel chicks in our Co. Kerry nestbox are just about fledged and have already left the nest box, though are hanging around outside (see post below). They are all still being fed by the parents at the nest box and in this clip we can see several food items being despatched by the two hungry youngsters still inside. First, one goes back to a small bird which is cached at the back of the box (probably either a young Grasshopper Warbler or a Meadow Pipit).

Soon after, one of the adults arrives with a 'prepared lunch', another, larger bird which has already been substantially plucked. Any guess as to which species this might be? Notice the chicks eat pretty much everything of the bird - head, feathers, legs and all.

Finally, just as the battery runs out on our camera, another prey delivery arrives to be snatched by one of the chicks, but from the size and colour, it looks to be a Bank Vole.

Thinking outside the box

Kestrel chicks, Co. Kerry, 1st July 2013 (Filmed under licence: Michael O'Clery).

Our nest box Kestrel chicks in Co. Kerry are nearly fully fledged. Two have now left and are hanging around outside and on top of the box. The two adventurers are both well capable of flying and were flying into nearby trees at times. The parents are still delivering food to the nest, so the fledglings seem reluctant to stray too far lest they miss a feed. Some footage of the two remaining chicks inside the box tomorrow.