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The dawn chorus of the black-capped chickadee (Poecile atricapillus) is a communication network that functions in the dissemination of essential information for both males and females. Habitat type may influence the performance of this network, and if recognized, chickadees may attempt to behaviorally compensate for detrimental changes in the form of increased movement. We studied the dawn chorus of 66 black-capped chickadees in two adjacent, yet structurally different, habitats (disturbed and undisturbed) during the summers of 2000-2003 and recorded via point counts the number of neighboring males heard singing simultaneously while following a focal chorusing male and observing his movement. A transmission study to detect differential degradation due to habitat type was also conducted within the same research site. Observers in the disturbed sites heard significantly fewer neighboring males in the focal male's territory than in the undisturbed site, yet individual movement did not differ between habitat types. Propagation of song of varying frequencies, as measured by entropy, suffered less degradation in the disturbed site for high-frequency songs, but there was no effect of habitat on low-or mid-frequency songs. Greater interneighbor distance in the disturbed site likely explains some of the reduction in audibility of neighboring males during the dawn chorus, but the reduced condition of birds in the disturbed site (implicated from other studies) may also be a factor in explaining the difference in networks. The findings of this study suggest that chickadees in the disturbed habitat are experiencing a compromised communication network, which could impact breeding and other social behaviors.

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Fishers (Pekania pennanti) are a forest-dependent carnivore of conservation concern in British Columbia, Canada. Ecological, spatial, and genetic evidence suggests that there are 2 distinct populations (Boreal and Columbian) that occur in forests at low to moderate elevations in the boreal and central interior regions of the province. In British Columbia, fishers occur at low densities relative to other parts of their range in North America, are trapped for their fur, and are sensitive to habitat change. Despite these factors, little demographic information exists to assist with management decisions for these populations. We collated and analyzed survival and reproductive data from 100 radio-tagged fishers from 5 independent studies conducted between 1990 and 2012 in British Columbia: 2 in the Boreal population, and 3 in the Columbian population. We also collated litter size data from 1 den box study and a translocation project of fishers from the Columbian population. Annual survival rates were not significantly different between the populations or between males and females; however, adult survival rates were higher than subadults (0.79 and 0.63, respectively). Subadult females had significantly lower survival rates than other sex or age classes. Reproductive rates were significantly different between the 2 populations (denning rate = 0.54 [Columbian], 0.82 [Boreal]; x ¯litter size = 1.7 [Columbian], 2.6 [Boreal]). These differences resulted in net reproductive rates in the Columbian population that were less than half of those in the Boreal population (0.92 kits/reproductive season compared to 2.13, respectively). Population growth rates suggest that the