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Research is presented concerning the impact which the even-aged management of forests has on the diversity and productivity of forest birds which live in mature forests. Clearcuts are compared with groupcuts.

Research is presented concerning the measurement of the dimensions of 391 burrows used by nesting seabirds in Alaska in order to determine a method of differentiating between bird species without disturbance to the birds.

Group selection is a technique that provides an alternative to clearcutting, but it creates more edge per unit than clearcutting. Therefore, if edge-related increases in nest predation exist in forest compared to groupcuts, group selection may result in higher rates of edge-related nest predation than does clearcutting. To examine this concept, researchers deployed 80 artificial shrub nests baited with Zebra Finch eggs in edge areas and interior areas. They found that the probability of nest depredation is higher in edge areas than interior areas.

Voluntary reporting of incidents of piping plover mortality showed that motorized off-road vehicles (ORVs) caused mortality to 18 unfledged piping plover chicks and two adults in 14 incidents on Massachusetts and New York beaches. ORV use may be due to administrative, recreational or service reasons. The piping plover chick behavior tendency to feed along intertidal zones increased their vulnerability to such accidents. Such areas should be closed to ORVs at least a day before hatch dates to prevent chick mortality.

The use of northeastern US wetlands by river otters (Lutra canadensis) was studied to determine the effects of wetland dynamics on river otter populations. Wetland types and seasonal variation in wetland use was characterized, using river otter latrine revisitation rates as an index of total habitat use. Results showed that river otter wetland habitats are those created by beavers and humans by impoundment, as well as lotic or unimpounded wetlands. Techniques for identifying river otter habitats are presented.

The construction, installation and use of circular, wire predator exclosures were discussed in a study to protect the endangered piping plover species. The wire-mesh exclosure was circular, 3. 2-m-diameter, costs 15 dollars and can be installed in an average of 9.5 minutes per exclosure. It was shown that hatching success was 74% higher in nests protected by the exclosures compared to those nests without the protective exclosures.

To determine if contaminants contributed to low hatching success of ospreys (Panditon haliaetus) nesting near Delaware Bay, we compared levels of organochlorines, mercury, and lead in addled and randomly collected eggs and potential prey from Delaware Bay to a successful population along the Atlantic Coast (

Reestablishment of the peregrine falcon (Falco peregrinus) as a breeding bird in the eastern United States is a highlight in endangered species management and recovery programs. We examined numbers of pairs, reproductive success, and eggshell thinning of a reestablished peregrine falcon population in New Jersey during 1979-88. Productivity of these falcons (x = 1.38 young fledged/pair) was comparable with that of stable populations, but productivity was lower (P = 0.02) for pairs near Delaware Bay and River (0.58 young/pair) compared to those in other regions of New Jersey (1.55 young/pair). Lower productivity and nest success of 4 pairs near Delaware Bay and River that we studied intensively in both 1987 and 1988 were due to low hatching success and predation, probably by great horned owls (Bubo virginianus). During 1985-88 eggshell thickness from New Jersey peregrines averaged 16.4% below pre-DDT levels and apparently has decreased steadily since 1979. This decrease in eggshell thickness statewide suggests that falcons continue to be exposed to environmental contaminants.

To determine factors responsible for low productivity of ospreys (Pandion haliaetus) nesting along Delaware Bay, we compared their reproductive success to birds nesting along the Atlantic Coast during 1987 and 1988. Productivity of ospreys nesting along Delaware Bay was lower because 50% of all nests initiated failed, whereas only 21% of Atlantic Coast nests failed. Only 50% of all eggs laid in the Bay colony hatched, compared to 69% in the Atlantic Coast colony. Nestling mortality was similar between colonies (26 vs. 18% for Delaware Bay and Atlantic Coast, respectively) but 21% of those young hatched near the Bay were probably preyed upon by great horned owls (Bubo virginianus). Although Delaware Bay ospreys spent considerably more time away from their nests, presumably foraging, than did Atlantic Coast birds, adults from both colonies spent similar amounts of time feeding young, which suggests that food stress did not influence productivity. High frequency of unhatched eggs and thinner eggshells (8% below pre-DDT levels vs. 3% for Atlantic Coast eggs) of ospreys along Delaware Bay suggests possible exposure to environmental contaminants that may reduce hatching success.