W. Cresswell, NEST PREDATION RATES AND NEST DETECTABILITY IN DIFFERENT STAGES OF BREEDING IN BLACKBIRDS TURDUS-MERULA, Journal of avian biology, 28(4), 1997, pp. 296-302
Nest predation in relation to nestling noise and nest conspicuousness
was investigated in Blackbirds. In one year there was no temporal vari
ation in nest predation or significant variation in nest predation rat
es due to nest conspicuousness. In a second year nest predation rates
were significantly higher in the early stages of breeding (laying and
the first half of incubation), and nests that were less conspicuous we
re more likely to survive longer or succeed. In both years there was n
o significant difference in nest predation rate between the second hal
f of incubation and the first half of the chick stage, but there was a
significant decrease in nest predation rate between the first and sec
ond half of the chick stage. The results suggest that increased noise
from nests during the chick stage did not increase the probability of
nest predation, and that if nest predation is important in determining
clutch size in Blackbirds, selection may occur early on in breeding.