Publications

Corridors have become a key issue in the discussion of conservation planning: however, few empirical data exist on the use of corridors and their effects on population dynamics. The objective of this replicated, population level, capture-re-capture experiment on meadow voles was to estimate and compare population characteristics of voles between (1) corridor-linked fragments, (2)...

This report clarifies recent studies on the saker falcon in Mongolia. In the last five years, three museum studies appeared on the Altay falcon (is it a gyrfalcon, saker or separate species). These showed that all of the most distinct Central Asian summer specimens were from only two mountain ranges. However, there is a continuum between sakers and Altay falcons and the two should be...

Stormwater treatment ponds receive elevated levels of metals from urban runoff, but the effects of these pollutants on organisms residing in the ponds are unknown. We investigated the accumulation of Cu, Zn, and Pb by macroinvertebrates collected from stormwater treatment ponds in Maryland serving commercial, highway, residential and open-space watersheds, and determined whether...

This study evaluated the toxicity of a single size 7.5 lead shot to passerines. No mortalities or signs of plumbism were observed in dosed cowbirds (Molothrus ater) fed a commercial diet, but when given a more natural diet, three of 10 dosed birds died within 1 day. For all survivors from which shot were recovered, all but one excreted the shot within 24 h of dosing, whereas, the dead...

No abstract available.

No abstract available.

Although the trend for the past 2 decades has been toward releasing naive groups of juveniles after a lengthy acclimation period, in 5 separate releases (1996-2000) we tested the idea that naive juvenile greater sandhill cranes (Grus canadensis tabida) would survive better if released singly into a wild flock of predator-wary birds than if left as a group, inexperienced at foraging and...

The migratory Rocky Mountain Population (RMP) of the greater sandhill crane (Grus canadensis tabida) breeds primarily in river valleys, marshes, and meadows of western Montana and Wyoming, southeastern Idaho, northern Utah, and northwestern Colorado. The RMP winters primarily in the Middle Rio Grande Valley of New Mexico, with smaller concentrations in the southwestern parts of that...

About 50% of the whooping cranes (Grus americana) released in Florida die within the first year of release. Most of these deaths and those in subsequent years result from bobcat (Lynx rufus) predation. Choosing release sites in open marshes away from bobcat habitat has improved survival. We hypothesized that exposure to ponds (water conditioning) at the rearing site would encourage birds...

We tested to see if semen collection interferes with fertility in naturally fertile pairs of cranes. We used 12 naturally fertile, Florida sandhill crane (Grus canadensis pratensis) pairs for this study, 6 control and 6 experimental. All pairs had previously produced fertile eggs. Semen was collected on Tuesday mornings and Friday afternoons from 26 February 1993 to 4 June 1993. We used

Ten experiments have been conducted to determine if cranes can be led on migration and if those so trained will repeat migrations on their own. Results have been mixed as we have experienced the mishaps common to pilot studies. Nevertheless, we have learned many valuable lessons. Chief among these are that cranes can be led long distances behind motorized craft (air and ground), and...

During the 1998 field season, we developed and tested a new protocol to teach sandhill cranes (Grus canadensis) to follow ultralight aircraft yet avoid humans. Although successful in teaching the cranes a migration route, our previous migration (1997) resulted in birds that were overly tame and sought association with humans. For this study, 16 sandhill cranes were costume-reared at USGS