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Satellite tagging of young kestrels
Annual kestrel summaries - Scotland
Annual Report 2005
Following the 2004 peak it was no surprise when, in response to the vole numbers dropping dramatically, the 2005 season was characterised by low territory occupation and a fall in productivity. From the onset it was clear that the number of kestrel pairs holding territory was significantly down with only 51% occupation compared to 84% the previous year. The weather was mixed all season erring on the dry but some of the scrapes in March were damp due to wind driven rain.
However this did not deter those birds on territory merely putting back the laying dates. There were some sizeable gaps between scrapes being made and eggs laid. One pair which had the nest site ready in mid March produced their first egg 47 days later by which time the nest site and immediate vicinity had a huge build up of droppings, pellets and down feathers.
The 2005 breeding statistics are as follows :-
|
|
2005 |
2004 |
2003 |
2002
|
|
Number of territories checked
|
35 |
33 |
30 |
34 |
|
% occupation
|
51 |
84 |
66 |
44 |
|
Number of clutches known
|
14 |
24 |
13 |
9 |
|
Average clutch size
|
4.5 |
5.5 |
5.46 |
4.4 |
|
% of eggs which hatched
|
74 |
92 |
83 |
82 |
|
Number of results known
|
14 |
26 |
20 |
12 |
|
Average young per breeding pair
|
3.2 |
4.2 |
3.1 |
2.75 |
|
Average young per successful pair
|
4.1 |
4.8 |
3.9 |
4.1 |
|
Number of breeding attempts failed
|
3 |
3 |
4 |
4 |
|
% failed
|
21 |
11 |
20 |
33 |
|
% brood survival
|
89 |
90 |
91 |
82 |
|
Number of young ringed
|
40 |
67 |
40 |
30 |
One pair bucked the trend both in timing of laying and clutch size. Laying on 1 April, a good 2 weeks before any other pair, the hen laid the only clutch of 6 eggs to be recorded in 2005 compared to 9 sixes and one 7 in 2004. Average clutch size dropped to 4.5 and hatching success was quite low at 74%. Although brood survival was as usual high there were signs that food was scarce – no cached food in nests, few signs of voles till towards the end of the season, several runts in broods and on one occasion half grown young birds actually nibbling at my fingers seeking food. Despite the obvious lack of voles ,productivity was reasonably good and few pairs failed Of the 3 which failed, one had its clutch stolen, and 2 deserted at the egg stage.
Two ringed birds were recovered, one 2004 young ringed near Straiton was found freshly dead near Dalry a distance of 49 Km from the natal site. The second, ringed in the hills to the east of Cumnock in 2004 was found dying near Bo’ness in Central Region a distance of 69 Km. Both birds died in their first winter, 8 January and 27 December respectively.