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Satellite tagging of young kestrels
Annual kestrel summaries - Scotland
Annual Report 2011
The season had a very encouraging start with very open and mild weather in late March and April. Territories were occupied early but the number of pairs was down on the previous year. The first egg was recorded on 2 April and another five first egg dates were recorded up to the 21st of the month. Reports of high vole numbers in Dumfries & Galloway and the eastern parts of Ayrshire were reflected in the clutch sizes which included five 6’s and six 5’s. However in most of the study areas the activity and signs on the ground, the excess voles in the nest sites, all indicators of vole peaks, were absent.
The crunch came in May with very wet and windy weather culminating in an extreme spell around the 23rd of the month with persistent gale force winds and driving rain. There were complete desertions of nests and the percentage of eggs which hatched was one of the lowest on record at 67%. As usual brood survival was high but the damage had been done and the breeding output reflected this.
The 2011 breeding statistics are as follows :-
|
|
2011 | 2010 | 2009 | 2008 | 2007 |
2006 |
|
Number of territories
checked |
38 | 37 | 39 | 41 | 34 |
35 |
|
% occupation |
63 | 73 | 49 | 73 | 59 |
72 |
|
Number of clutches
known |
11 | 15 | 10 | 18 | 12 |
16 |
|
Average clutch
size |
5.45 | 5.2 | 4.6 | 5.3 | 5.25 |
4.75 |
|
% of eggs which
hatched |
67 | 89 | 91 | 83 | 95 |
84 |
|
Number of results
known |
24 | 25 | 19 | 26 | 17 |
25 |
|
Average young per
breeding pair |
2.8 | 3.8 | 2.8 | 3.81 | 4 |
3.2 |
|
Average young per
successful pair |
3.5 | 4.4 | 3.4 | 4.3 | 5.15 |
3.8 |
|
Number of breeding
attempts failed |
5 | 3 | 4 | 3 | 3 |
4 |
|
% failed |
21 | 12 | 21 | 11 | 17 |
16 |
|
% brood
survival |
89 | 89 | 90 | 96 | 93 |
98 |
|
Number of young ringed |
20 | 34 | 23 | 46 | 44 |
46 |
Number of field days: 33
For the first time in many years two pairs relaid, rearing three and two young respectively, the latter leaving the nest in the first week of August, which is extremely late. Six family parties recorded in the field but where the nest site had not been located averaged 2.5 young per group. The five failures all occurred at the pre-laying or clutch stage, three due to desertion in bad weather, and the other two due to competition from other species.
The only ringing recovery was notable, a male ringed in 2004 at Culzean Country Park was found badly injured 16 kilometers from its natal site surviving a creditable seven years.
At one territory both kestrel and peregrine pairs bred on the same crag only 20 feet apart, and both reared young successfully.