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Recent evidence suggests that population declines in many Neotropical-wintering migratory landbird species are caused by habitat loss and degradation on their wintering grounds. Such habitat loss and degradation can lower overwintering survival rates and cause surviving birds to leave their wintering grounds in poor physical condition, leading to high mortality during spring migration and low breeding productivity. Large-scale, long-term data on winter demographic parameters of these species and linkages between those parameters and winter habitat characteristics are urgently needed to...

We compared a set of competing logistic regression habitat selection models for Northern Spotted Owls (Strix occidentalis caurina) in California. The habitat selection models were estimated, compared, evaluated, and tested using multiple sample datasets collected on federal forestlands in northern California. We used Bayesian methods in interpreting Akaike weights calculated for the estimated models. This approach combines Akaike weights with prior probabilities to provide posterior probabilities for the set of competing models for each dataset. This process can be iterated with multiple...

In this paper we argue that effective management of landbirds should be based on assessing and monitoring their vital rates (primary demographic parameters) as well as population trends. This is because environmental stressors and management actions affect vital rates directly and usually without time lags, and because monitoring vital rates provides a) information on the stage of the life cycle where population change is being effected, b) a good measure of the health and viability of populations, and c) a clear index of habitat quality. We suggest that modeling lambda (λ, the rate of...

An indirect estimate of juvenile survival was derived for a closed, small, population of Black-capped Vireos (Vireo atricapillus) in the Wichita Mountains, Oklahoma monitored since 1987. I used seasonal fecundities of vireos in years when the population was stable in the formula for intrinsic growth rate to solve for juvenile survival. The derived probability of juvenile survival to breeding was 0.40-0.57, more than two-thirds the annual adult-female survival. This result parallels the observations of Nolan (1978) for Prairie Warblers (Dendroica discolor). It suggests that the conservative...

The year 2002 marks the 100th anniversary of scientific bird banding in North America. Credit for the first banding goes to Dr. Paul Bartsch of the Smithsonian Institution, who in 1902, banded 23 Black-crowned Night-Herons (Nycticorax nycticorax) at Washington, DC (Bartsch 1904). Others, especially P. A. Taverner, Leon Cole, and the American Bird Banding Association, were involved with in the early development of bird banding in North America, but none was so influential as Frederick C. Lincoln. Building on previous attempts to organize bird banding, Lincoln formed a continental program...

Acquiring an accurate picture of the changes in bird populations often involves a trade-off between the time and effort required to complete the surveys and the number of years spent surveying the bird populations. An alternative approach to long-term monitoring efforts is to collect current data and contrast those with data collected earlier in a similar fashion on the same study site(s). To evaluate changes in bird populations, we repeated two extensive surveys, one in North Dakota (1967 vs. 1992-1993) and the other in the Platte River Valley of Nebraska (1979-1980 vs. 2001), where large...

Since 1994, the Tortuguero Integrated Bird Monitoring Program has been monitoring birds in a coastal lowland rain forest of northeast Costa Rica. The Program has combined the use of area searches, constanteffort mist netting, and migration counts into a longterm landbird monitoring and training program following the recommendations of the Partners In Flight – Aves de las Américas monitoring guidelines. We briefly summarize the methods and results from our monitoring, including the numbers of bird species captured, censuses from 1994 through 2002, and age ratios for five species of migrant...

We used 4-hr tape recordings to assess singing activity of a Least Bell's Vireo (Vireo belli pusillus) on 7 d distributed throughout the breeding season of 2001. We logged 9873 songs, for a mean singing rate of 5.84 min-1, but despite this level of activity, the bird was silent during 33 percent of the 1691 minutes of the study. Availability, the proportion of minutes in which singing activity occurred (and hence the probability of at least one song occurring in any randomly selected minute) varied from 0.36 to 0.96. As availability is a major component of detection probability, we tested...

The success of avian monitoring programs to effectively guide management decisions requires that studies be efficiently designed and data be properly analyzed. A complicating factor is that point count surveys often generate data with non-normal distributional properties. In this paper we review methods of dealing with deviations from normal assumptions, and we focus on the application of generalized linear models (GLMs). We also discuss problems associated with overdispersion (more variation than expected). In order to evaluate the statistical power of these models to detect differences...