Chick Ringing

I spent all of yesterday with John Lusby, my line manager at BirdWatch Ireland, visiting all of our known West Offaly Kestrel and Long-eared Owl nests. We were monitoring the nests both to record the productivity of each brood and also to ring any chicks that were large enough to do so. To save on a lot of unnecessary ladder and rope play we brought with us a nice new piece of kit. A nest inspection device, and what this effectively is, is a camera on top of a long pole. With all the subtleties of motion which we could summon, we maneuvered our 10m long nest inspection device into position in the hope of an illuminating view of the nest contents. All active nests at this time of year for both Kestrels and Long-eared Owls will have either eggs or chicks. Counting the downy chicks from the picture provided on the small screen of the camera can be a bewildering prospect. At first glance you are faced with a downy mess, of a nondescript nature, but gradually you begin to notice the border lines which separate individuals. Should the chicks be large enough to ring, phase two of the operation begins. The pictures below, in the order in which they appear are a Kestrel chick, Long-eared Owl chick and a close up of the amazing eyes of the same.

A ladder and/or a rope are used to reach the chicks in their lofty nests. In the case of a building a ladder is used and the operation becomes a more straight forward procedure. In the case of the nest being positioned in the extremities of a large tree, John our resident arboreal expert is called into play. Firstly John shots a guide line up into the top most branches which creates an anchor point, which will support his weight while he climbs. Using a maze of knots, a pulley system and not an inconsiderable amount of industry, the tree is climbed and the chicks ringed. Along with the ring number the bird’s age, health and place of birth are recorded.

As these chicks fledge and inevitably disperse, future encounters with them (thanks to the rings), will help to lessen the vale of ignorance which surrounds the lives of these enigmatic birds of prey.  

The Musical Owl

Really nice to have a little warmth in the sun yesterday, the night itself too didn’t have the usual chill factor. I was out on the night shift last night looking for Long-eared Owls. More specifically I was out listening for Long-eared Owl chicks calling (pictured below by John Lusby). The books describe their begging calls to their parents as akin to the sound of a rusty gate squeaking.  This rusty gate analogy for me doesn't fit. Their calls are not at all a sound which would make you wince. The Long-eared Owl chick’s begging is a single, pleasant, drawn out note which seems to somehow fit naturally into the summer night’s soundtrack. The sound doesn't demand your attention but once you’re listening for it the high pitched notes are unmistakable.

The birds which I visited last night are resident on the edge of a rookery. I couldn’t see the nest itself in the nighttime gloom blow a Scots Pine stand but the chicks are not at all shy. I didn't see the chicks either, but standing below the tree they could be easily pinned down to a branch or two from their calls alone. The sound too really travels, I could hear the chicks from at least a kilometer away. I gathered from their chorus, that there were three chicks. One at least has fledged and called from a tree some 30m away. Young Long-eared Owls fledge early, leaving the nest while still flightless and covered in down. This behaviour is thought to be a defence mechanism to guard against predation on the nest. If any of the nestlings are to be ringed, we’ll have to visit the nest site soon before the two remaining chicks have fledged. 

The weather seems to be on the up for the next week at least so why not get out for an evening stroll, and who knows maybe a harmony of Long-eared Owl chicks are playing a wood near you!

Out With the Old in With the New

Last Friday evening I undertook a roost watch at an old castle, which is set in an idyllic area of farmland surrounded by encircling broad leaf woodland. The building is quite well preserved, it lacks a roof but its bell tower and thick buttressed walls remain intact. It must have supported a large community of people in times past, with its many rooms and network of passages. However its present day residences are of an entirely different sort. The building plays host to a large and healthy population of Jackdaws, a pair of Ravens (pictured second below by Stephen McAvoy) and a pair each of Kestrels and Barn Owls (pictured first below by Andrew Kelly). Swifts and Starling complete the list of amorous breeding inhabitants.

I arrived at 20:20 which is an hour before sunset, in the hope of catching sight of the Kestrels before I entered the castle to find the Barn Owl nest site. Happily the Kestrels were not feeling particularly shy, and on arrival the male bird roosted passively on a castle drain pipe for some twenty minutes before heading off to hunt. While I waited for his return, the ravens entertained me with their antics. They wheeled and circled, periodically herding and scattering the Jackdaws of the castle. The sun had set and it was near dark before I had sight or sound of the male Kestrel again. He flew in and resettled himself on his earlier perch and was joined by his mate. Even in the shaded light of this chilly evening the sexes could easily be told apart by size alone. As is common for many raptors the female is the larger of the two. The female finally showed me what I had come to see, her nest entrance just as the light was near fully gone. She flew lightly from her window ledge perch to an arrow slit widow and disappeared from view to resume her incubation of this year’s brood. Phase one of the mission of the evening complete I entered the castle.

Buoyant with my earlier success, I didn't have to wait long before I heard the gentle snoring of the female Barn Owl. This snoring is in fact the begging call (young Barn Owls snore too) which stimulates the male to leave to hunt. A snoring female confirms breeding, which meant my evenings work was complete with both nests found. Success!

Hidden Gems

What miserable weather we’re having today, fortunately Thursday of last week was much nicer which allowed me (and a colleague John Lusby) to get out and check some of my known West Offaly Kestrel nest sites. As promised below is a picture of the inside of a Kestrel nest. These striking specked eggs are from a Kestrel nest in an old ruined mansion just outside Banagher village. The female flushed quite quickly on our arrival on site, the only remaining trace of her was a single moulted feather. Not altogether untypically she remained quite close, often circling overhead, keeping a close watch on proceedings. We were in and out in no time, which happily allowed the female to soon return to her precious six strong clutch. Six is the maximum number of eggs which has been recorded by Birdwatch Ireland at a Kestrel nest. This nest fledged five birds last year, so hopefully similar success is in store in the weeks and months to come.

Although the majority of Kestrel nests which we visited on Thursday were on eggs, there is however quite a degree of variation in timing between pairs. Another site just outside Ferbane hosts a pair who haven't settled down to it yet. The birds are still soaring around their castle abode, a courtship behaviour usually seen earlier in the season. Another pair close by, which I spend a morning with in order to pin down their nest, spent a three hour period copulating and courting. A degree of variation in timing of breeding is natural in a population, with younger birds often being the last to settle down to breed.    

Spring has sprung for most other species and is wearing on, into a hopeful summer. This Chaffinch brood for example, pictured below will be fledging any day now. The nest is perfectly camouflaged at the centre of this Hawthorn bush. The young birds pleads’ for food, being the only clue to their presence. Their industrious parents scolded me angrily, as I took this picture. Continue to keep an eye on the blog for more updates and pictures as the breeding season kicks into overdrive in the coming weeks.

The Windhovers!

The Kestrel is Ireland’s most commonly seen raptor species, it is the only bird of its size (being roughly comparable in size with our cities feral pigeons) to hover and it is most often observed doing just this along motorways. Hunting in this manner, Kestrels are searching for small mammals which make up the vast majority of their diet. To aid them in this search, Kestrels have evolved an extraordinary means by which to track their prey. Kestrels can see in near ultraviolet light. In ultraviolet light the urine droplets which rodents use to mark their territories shine in sunlight, this territorial practice thereby unwittingly drawing their predator upon them. Although this species is widespread and commonly seen, its population is declining in the state, which has increased fears for the health of the wider ecosystem*.

Yesterday May 1^st, was the first day of the project's vantage point survey for Kestrels within the 10km square encompassing Ferbane (IN12). Vantage point surveys are designed to record the flight activity patterns of birds. This method is commonly used to assess the possible impact of a wind farm on a bird community. Vantage point surveying is often a prerequisite before planning permission can be awarded to such industries. In my case however, I am interested in breeding densities of Kestrels in the area. It is hoped by recording the activities of Kestrels, activity ‘hot spots’ will come to light. The activity ‘hot spots’ will then be used to establish the number of breeding territories in the locality. Unfortunately high ground is at a minimum around Ferbane. The area is quit flat, with a patchwork of fields encircled with mature hedgerows. Although this will make vantage point surveying more difficult, it does however make for very pleasant surroundings in which to work.

There are six known, to BirdWatch Ireland (BWI), Kestrel breeding sites in West Offaly. This number cannot in reality represent the true number of breeding birds in the area, it is for this reason that I reiterate my appeal for any sighting to be reported to BWI.  Kestrel nest in a variety of different sites, ranging from old corvid nests in trees to ledges in abandoned buildings. The above pictures show an old castle from the outside and the second picture shows the inside where the nest site is located on the top shelf. The six active sites are in full swing. The males are making frequent visits to nests, to supply their sitting mates with food and support. One instance, on visiting a Kestrel nest in a monkey puzzle tree, I saw the male bird’s defensive abilities in full effect. He repeatedly dive bombed a Hooded Crow who was loitering in the locality of the tree. Given the Hooded Crow’s reputation for egg robbery, this intervention seemed particularly necessary. Kestrel females will generally be on broods of 4-6 eggs at present which they will brood typically for around a month. Both parents will then provision the resulting chicks for a further month before fledging. It is hoped that we will revisit each of these nests in this period before fledging to ring the chicks. Ringing helps in establishing survival and dispersal rates of young birds.

To further help breeding Kestrels in West Offaly, a nest box scheme will be rolled out later this summer. The boxes are being built by the local secondary school Banagher College and Tus. The boxes are useful on two fronts both as a conservation measure and they also make monitoring nest sites easier. This is a really important part of the project and I can’t thank Tus (myself and two of the Tus works below) and Banagher College enough.

The project will be concentrating on surveying for Kestrels during May. Keep an eye on the blog in the coming weeks for pictures of some of the Kestrel nests I will be visiting. Also Kestrels will be very active this month, keep an eye out for males carrying prey in their talons, this is a sure sign that Kestrels are breeding in your area.

     

*The Kestrel Falco tinnunculus is a top avian predator of the wider countryside, and as such is an excellent sentinel of environmental health. Pollutants in the environment are most strongly felt by top predators. The Kestrel has a widespread distribution throughout Europe, it is listed as a Species of European Conservation concern (SPEC 3). In Ireland the Kestrel population has declined by 15% between the first Breeding Atlas (1968-1972) and the New Breeding Atlas (1988-1991). The Irish population is on the Amber list of the Birds of Conservation Concern in Ireland. Factors previously implicated in the Kestrels decline are agricultural intensification leading to the loss of suitable foraging habitat, the loss of nest sites and climate change.