The Kestrel in Ayrshire - annual report 2008

Kestrels For Company

available in bookstores

Annual Report 2008

Following two poor vole years it was encouraging to see high clutch sizes in the early part of the season – half-a-dozen sixes and nine clutches of five indicated amply food availability and females in good condition. However as the season progressed into the brood period it was noticeable that there was no surplus food in any nests, a sign of decreasing vole numbers. Productivity per pair was down on 2007. The probability is that the voles peaked in the latter part of 2007 and early 2008 then fell hack as the year went on.

The weather in the early part of the season was mixed in March and April and excellent in May. This was followed by a sunny and dry first half of June and mixed second period. This mix of weather suits the kestrel and both hatching success and brood survival was high. Territory occupation was good at 73 per cent, the first egg was laid on April 2 and the first young were seen in the air on June 7. The range of first egg laying dates was from April 2 to May 7.

The 2008 breeding statistics are as follows :-

	2008	2007	2006	2005	2004	2003	2002

Number of territories checked	41	34	35	35	33	30	34
% occupation	73	59	72	51	84	66	44
Number of clutches known	18	12	16	14	24	13	9
Average clutch size	5.3	5.25	4.75	4.5	5.5	5.46	4.4
% of eggs which hatched	83	95	84	74	92	83	82
Number of results known	26	17	25	14	26	20	12
Average young per breeding pair	3.81	4	3.2	3.2	4.2	3.1	2.75
Average young per successful pair	4.3	5.15	3.8	4.1	4.8	3.9	4.1
Number of breeding attempts failed	3	3	4	3	3	4	4
% failed	11	17	16	21	11	20	33
% brood survival	96	93	98	89	90	91	82
Number of young ringed	46	44	46	40	67	40	30

Number of field days: 33

Overall the season was productive, the main interest being the three failed breeding attempts. One was at the pre-laying stage but the other two were caused by owl activity, one nest site taken over by barn owls after the kestrels had laid a clutch of five eggs, and the other where a brood was predated at ten to twelve days and tawny owl feathers were found in the nest. At another site a tawny owl blinded the hen kestrel but the cock bird raised the brood of five assisted by supplementary feeding. A remarkable achievement as the young were not at the stage of feeding themselves when the incident occurred. A female peregrine was seen taking a fully fledged kestrel youngster at a quarry site. Inter specific competition and predation is obviously a very important factor in breeding productivity today.