Publications

No abstract available.

During 11-15 March 1986, we visited Cat Island in the Bahamas. Here we report on 27 species of birds whose status on Cat Island is poorly known, including eight for which no pervious records exist.

More than 1,000 food items, representing 32 species of fish and one invertebrate, were identified from olivaceous cormorants. Six species of fish comprised 79% of the diet by frequency of occurrence and 78% by weight. Almost half of the diet consisted of a single species, the sheepshead minnow. Concentrations of pp-dichlorodiphenyldichloroethylene (DDE) in cormorant carcasses were 27 times grea

Estimates of longevity are available for many animals, and are commonly used in comparative life-history analyses. We suggest that annual survival rate is more appropriate life history parameter for most comparative life history analyses. Observed maximum longevities were not correlated with the annual survival rate estimates and appear to be unstable over time. We recommend that observed maxim

About 110 wolves in 13 packs inhabit Denali National Park. Pack sizes vary from 2 to 15 in winter, and minimum pack territory sizes range from 250 to 805 square miles.

American black ducks, Anas rubripes, were marked and recaptured along mid-coastal Maine between the winters of 1979 and 1985 to examine the relationship between body mass and annual survival. Binary regression analyses indicated that late-winter body mass was not positively related to annual survival for any age-sex class.

More than 500 food items of nestling Black Skimmers were identified representing 18 species of fish and 2 invertebrates. DDE and poly-chlorinated biphenyls (PCBs) were the only contaminants consistently detected in the black skimmer diet, carcass, and egg samples. Eggs contained 14 times the level of PCBs detected in the fish diet.

An improved method of automatically monitoring nest attentiveness was designed and tested using radio-equipped American Woodcock (Scolopax minor). Shielded coaxial cable (RG-58) was extended from a receiver and placed 30 cm above the nest, with a 3.8 cm section of the inner wire exposed. Presence, absence, and activity of birds within 10.1 ? 5.2 m (SD) of the nest were clearly indicated on a Rustr

Double-crested Cormorants (Phalacrocorax auritus) in extreme northwestern Washington produced few young (0.27/occupied nest) in 1984; the clutch size was generally small and eggs, if laid at all, were laid later than usual. Residues (geometric means, wet weight) of DDE (0.58 and 0.59 ppm) in eggs from Colville Island and Protection Island were lower than from other locations in the Pacific Northwe

Behavioural dominance was studied in captive American black ducks (Anas rubripes) during October-December 1984. Eighty ducks were marked individually, and groups of 10 ducks consisting of 5 adults (3 males and 2 females) and 5 juveniles (3 males and 2 females) were assigned to each of 8 experimental pens. Ducks in 4 pens received an ad libitum diet, and ducks in the other 4 pens were given a restr

At DDE levels in eggs above 4 ppm, clucth size and productivity decreased, and the incidence of cracked eggs increased. Assuming that 4 ppm DDE is the critical residue level, 40% of the nesting population in 1985 and 1986 was adversely impacted by DDE, with a net loss of 20% of the population's expected production. Selenium and mercury were both accumulated by ibis on the breeding grounds in Ne

Plants, aquatic insects, and mosquitofish were collected from Kesterson Reservoir, Merced County, California, and a nearby reference site (Volta Wildlife Area) to compare concentrations of three contaminants found in 1985 with those reported in 1983 and 1984. Mean selenium concentrations in food-chain organisms from sites at Kesterson in 1985 ranged from 27.0 ug/g dry weight in water boatman to 1