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Satellite tagging of young kestrels
Annual kestrel summaries - Scotland
Annual Report 2004
The peak vole year materialized as expected (a carry over from 2003) but it tailed off towards the end of June. It proved to be an extremely productive season for the kestrel. Territory occupation at 84% was very high and there was a great deal of activity in March and early April despite some cold, wet and windy conditions, normally a deterrent.
The main upland study area was almost at full occupation at 11 pairs and at one site there was possibly polygamy with one male breeding successfully with one female and spending a lot of time with another at a nest box only a couple of hundred meters away. Although unable to verify the connection positively the interaction between the two sites was continuous. The second attempt failed.
Remarkably the first egg was laid in the same territory which has had the honour for many years despite changes in the hen bird. Fourteen dates were definitely gauged when the first egg was laid, the early one on 27 March, one on 6 May and the remainder between 11 and 26 April. Clutch sizes were at the top of the range with nine 6’s and one 7, a measure of the year with an average of 5.5 per completed clutch.
The 2004 breeding statistics are as follows :-
|
|
2004 |
2003 |
2002
|
|
Number of territories checked
|
33 |
30 |
34 |
|
% occupation
|
84 |
66 |
44 |
|
Number of clutches known
|
24 |
13 |
9 |
|
Average clutch size
|
5.5 |
5.46 |
4.4 |
|
% of eggs which hatched
|
92 |
83 |
82 |
|
Number of results known
|
26 |
20 |
12 |
|
Average young per breeding pair
|
4.2 |
3.1 |
2.75 |
|
Average young per successful pair
|
4.8 |
3.9 |
4.1 |
|
Number of breeding attempts failed
|
3 |
4 |
4 |
|
% failed
|
11 |
20 |
33 |
|
% brood survival
|
90 |
91 |
82 |
|
Number of young ringed
|
67 |
40 |
30 |
Ninety two percent of eggs hatched, brood survival was on a par at 90% and only 3 attempts failed – one when a hen failed to attract a mate, one deserted at the single egg stage in bad weather and another deserted its clutch in an old exposed crows nest in the face of continuous harassment from crows. Productivity was exceptionally good with successful pairs fledging 4.8 young and all attempts recording a healthy 4.2. Sixty seven young were ringed.
Three ringing recoveries were received including number 100, a young bird ringed near Maybole on 21 June 2001 found dead at Balmeddie Grampian, 103 days later, a good example of the random early dispersal of fledged young before the main shift south. Another ringed at one of the Dams in May 2003 was found only 13 kilometers from its natal site after 228 days, being the exception that proves the rule. The third ringed near Carsphairn in June 2000 was found in Cumbria in early December having travelled 135 kilometers.