Nest Survival

Spruce Grouse (Falcipennis canadensis) are listed as threatened in Wisconsin, and the boreal habitats in which they occur are likely to be threatened by changing climatic conditions. However, the limited information available on Spruce Grouse in the Upper Great Lakes region makes it unclear which habitat features are important for Spruce Grouse nesting in Wisconsin. We radiotracked 30 female Spruce Grouse in northern Wisconsin from 2007–2012 and located 25 nests. Eighteen of 25 nests were beneath black spruce (Picea mariana) trees. Only three nests were in upland, and only one in a stand of jack pines (Pinus banksiana), in contrast to studies from Michigan and Ontario. Overall concealment was a good predictor of nest sites for Spruce Grouse, but not a good predictor of nest survival. Nest survival was associated with moderately dense and uniform 0–0.5 m lateral vegetation cover. Seventeen of 25 nests were successful, with a daily survival rate of 0.985, overall productivity of 1.0 young/female, and 1.9 young/successful nest. Annual survival of adult males was estimated at 54%, adult females at 40%, and juvenile survival at 14% and 24% by two different methods. Estimates of l of 0.65 and 0.67 suggest a declining population, but the upper confidence limit exceeds 1, not ruling out a stable or slightly increasing population. Protecting black spruce swamps will protect important nesting habitat for Spruce
Grouse in Wisconsin.

We estimated nest survival and evaluated factors
affecting this demographic parameter for the Black Catbird
(Melanoptila glabrirostris), a poorly known mimid endemic
to the Yucata´n Peninsula. During the 2008 and 2009 breeding
seasons, we monitored 136 nests spread across four sites in
Mexico, including three mainland coastal sites in the Sian
Ka’an Biosphere Reserve and one site on Cozumel Island.
We documented higher nest loss in the mainland sites (74 %
failed) in contrast to the island site (21 % failed). Based on
our observations, we suspect that predation was the main
cause of nest failure. Using logistic exposure models and
Akaike’s Information Criterion, we found date, nest age, and
nest type to be the main factors influencing nest survival. Nest
survival was lower for open cup-nests in comparison with
semi-cavity nests. Interval nest survival (proportion of nests
expected to survive the entire nesting season) was 0.102
(CI = 0–0.660) for open-cup nests and 0.618 (CI =0–0.981)
for semi-cavity nests. Additional research on adult and
juvenile survival and dispersal patterns, especially for the
mainland population, is needed to determine if these rates of
nest survival are sufficient to maintain stable populations.