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.