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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.