Sterna, bind 15 nr 3 (PDF-fil) - Museum Stavanger

danger had passed. If the female bird was suspicious of danger, instead of
returning to the nest she would fly from place to place around the nest,
never staying in one place for more than a minute. This process rnight be
kept up for as long as half an hour, til1 the bird made sure that danger had
passed.
Clutch and Egg Size.
The first clutch found hatched was found in Nest 11 on 29th June 1973,
which had 6 young. Nest 18, found on 3rd July, was also hatched, having 6
young.
The clutch size varied from 4 (four) to 7 (seven) eggs.
Nest 6
5 eggs
Nest 7 - 4 eggs
Nest 11 - 6eggs
Nest 12 - 7 eggs
Nest 18 - 6 eggs
Mean clutch sizc .- 5.60 eggs.
Egg size also varied, although it was possible to measure only a total of
11 eggs, owing to inaccessibility, the figures suggest that larger clutches may
have smaller eggs.
Nest 7: Length of eggs in cm. Width of eggs in cm.
2.23 1.64
2.32 1.63
2.23 1.64
2.37 1.63
Mean Length - 2.287 Mean Width - 1.635
Nest 12: Length of eggs in cm.
2.05
2.08
2.09
2.05
2.00
2.10
2.09
Mean Length - 2.066
Width of eggs in cm.
1.67
1.60
1.65
1.68
1.60
1.60
1.59
Mean Width - 1.627
Nests 7 and 12: Overall Mean Length - 2.176
Overall Mean Width - 1.631