Items

2009

(n = 18)

2010

(n = 28)

2011

(n = 12)

Mean value

P

Inner diameter/cm

38.8 ± 2.4

37.4 ± 2.2

37.4 ± 1.8

37.8 ± 3.0

0.079

Depth of nest/cm

10.0 ± 1.9

9.1 ± 1.9

9.0 ± 1.3

9.4 ± 1.8

0.198

Distance between nests/cm

81.5 ± 8.2

78.9 ± 16.9

75.9 ± 10.4

79.1 ± 13.4

0.546