Paul W. Sykes

Evaluation of Mist-net Sampling as an Index to Productivity in Kirtland's Warblers

Many applied and theoretical investigations require information on how productivity varies in time and space (Temple and Wiens 1989, DeSante 1995). Examples include studies of habitat quality, population trends, life-history tactics, and metapopulation dynamics. From a demographic perspective, reproductivity is the number of young, counted at a given time of year, produced per adult (e.g. Caswell 1989). Various measures have been used to estimate productivity. One of the most attractive is mist neting during the summer after young have left the nest, but ideally before they have left the studv area. Several programs use this approach, including the Constant Effort Sites Scheme of the British Trust for Ornithology (Baillie et al. 1986 Bibby et al. 1992) and the Monitoring Avian Productivity and Survivorship {MAPS) program (DeSante et al. 1993) in North America.

FACTORS INFLUENCING COUNTS IN AN ANNUAL SURVEY OF SNAIL KITES IN FLORIDA

Snail Kites (Rostrhamus sociabilis) in Florida were monitored between 1969 and 1994 using a quasi-systematic annual survey. We analyzed data from the annual Snail Kite survey using a generalized linear model where counts were regarded as overdispersed Poisson random variables. This approach allowed us to investigate covariates that might have obscured temporal patterns of population change or induced spurious patterns in count data by influencing detection rates. We selected a model that distinguished effects related to these covariates from other temporal effects, allowing us to identify patterns of population change in count data. Snail Kite counts were influenced by observer differences, site effects, effort, and water levels. Because there was no temporal overlap of the primary observers who collected count data, patterns of change could be estimated within time intervals cov- ered by an observer, but not for the intervals among observers. Modeled population change was quite different from the change in counts, suggesting that analyses based on unadjusted counts do not accurately model Snail Kite population change. Results from this analysis were consistent with previous reports of an association between water levels and counts, although further work is needed to determine whether water levels affect actual population size as well as detection rates of Snail Kites. Although the effects of variation in detection rates can sometimes be mitigated by including controls for factors related to detection rates, it is often difficult to distinguish factors wholly related to detection rates from factors related to pop- ulation size. For factors related to both, count survey data cannot be adequately analyzed without explicit estimation of detection rates, using procedures such as capture-recapture.

Reproductive Status of the Shiny Cowbird in North America

Abstract We collected 17 (13 females, 4 males) Shiny Cowbirds (Molothrus bonariensis) during the passerine nesting season in July 1999 and 2003 in Jasper County, southwestern South Carolina. Five females (38%) were laying eggs, as ascertained from the condition of their reproductive organs. Two females collected on 1 July 1999 and 19 July 2003 had eggs in their oviducts, and would have deposited eggs within 1 day. Shiny Cowbirds have been in North America for at least 24 years, but only males had been collected before this study. Most of those collected had enlarged testes, as did the four collected in the present study, but these data are not proof that breeding actually occurred. The reproductive condition of the females we collected provides material evidence that the species breeds in North America. It is not known which species are being parasitized by Shiny Cowbirds, but several species widespread in the southeastern United States are highly suitable hosts.

First breeding records of whooper swan and brambling in North America at Attu Island, Alaska

We document the first breeding records of Whooper Swan (Cygnus cygnus) and Brambling (Fringilla montifringilla) in Alaska and North America on Attu Island in the Western Aleutians in the spring of 1996. Five cygnets were seen with adults and the nest located, and a territorial pair of Bramblings was observed and a nest with eggs found.

Pesticide Concentrations in Snail Kite Eggs and Nestlings in Florida

Concentrations of organochlorine pesticides were first reported in the Snail Kite (Rostrhamus sociabilis) and its principal prey, the apple snail (Pomacea paludosa), by Lamont and Reichel (Auk 87:158-159, 1970), using material from Conservation Area 2A (CA2A) and Loxahatchee National Wildlife Refuge (NWR) in the northeastern part of the Florida Everglades, all collected between 1965 and 1967. Treatment of Surinam rice fields in 1971 with sodium pentachlorophenol (NaPCP) to control populations of freshwater snails (Pomacea glauca and P. lineata) that resulted in a die-off of Snail Kites was described by Vermeer et al. (Environ. Pollut. 7:217-236, 1974). They found high levels of NaPCP in tissues of 17 kites that they analyzed, and they attributed mortality to NaPCP poi-