Skip to main content
U.S. flag

An official website of the United States government

Publications

These publications showcase the significant science conducted in our Science Centers.

Filter Total Items: 16966

Details of a confrontation between two wild wolves Details of a confrontation between two wild wolves

A confrontation was photographed and video-taped at close range between a wild alpha mate wolf (Canis lupus) of known history and an alien adult on Ellesmere Island, Northwest Territories, Canada. For 100-110 seconds the two stood near each other, maneuvered around, and snapped at each other until the alien fled. The alpha and his mate, who suddenly joined the encounter, chased the other...
Authors
L.D. Mech

Site tenacity of the endangered palila Site tenacity of the endangered palila

Strong site tenacity might prevent Palila (Loxioides bailleui), an endangered Hawaiian honeycreeper, from repopulating favorable habitats in their former range. We used radio telemetry during the nonbreeding and breeding seasons to study movements and dispersal rates of 57 Palila. All Palila remained in the study area, and home range sizes and movement distances were small relative to...
Authors
S.G. Fancy, R.T. Sugihara, J.J. Jeffrey, J.D. Jacobi

Efficiency and optimal allocation in the staggered entry design Efficiency and optimal allocation in the staggered entry design

The staggered entry design for survival analysis specifies that r left-truncated samples are to be used in estimation of a population survival function. The ith sample is taken at time Bi, from the subpopulation of individuals having survival time exceeding Bi. This paper investigates the performance of the staggered entry design relative to the usual design in which all samples have a...
Authors
W.A. Link

Cryopreservation of American kestrel semen with dimethylsulfoxide Cryopreservation of American kestrel semen with dimethylsulfoxide

Semen samples from 15 male American Kestrels (Falco sparverius) were frozen in dimethyl sulfoxide (DMSO). The semen was thawed 1-14 mo later and used to inseminate six females during three breeding seasons. Kestrels inseminated with thawed semen containing 4% DMSO produced only infertile eggs (N = 14). Kestrels inseminated with thawed semen containing 6%, 8%, or 10% DMSO produced fertile...
Authors
G.F. Gee, C.A. Morrell, J. Christian Franson, Oliver H. Pattee

Selenium accumulation and loss in mallard eggs Selenium accumulation and loss in mallard eggs

Five female mallards (Anas platyrhynchos) that had just started egg laying were first fed a diet containing 15 ppm selenium in the form of selenomethionine for 20 d and then an untreated diet for 20 d. Selenium levels in eggs peaked (to about 13-20 ppm) in about two weeks on the treated diet and leveled off at a low level ( 5 ppm) after about 10 d back on the untreated diet. Selenium...
Authors
G. H. Heinz

Identifying sex and age of apapane and iiwi on Hawaii Identifying sex and age of apapane and iiwi on Hawaii

Methods to determine the sex and age of Apapane (Himatione sanguinea) and Iiwi (Vestiaria coccinea) were developed on the basis of 189 museum specimens and 91 live birds captured in mist nets on the Island of Hawaii (USA). Both species retain all juvenal primaries and some juvenal secondaries and body feathers after the first prebasic molt and attain full adult plumage after the second...
Authors
S.G. Fancy, T.K. Pratt, G.D. Lindsey, C.K. Harada, A.H. Parent, J.D. Jacobi

Re-exposure of mallards to selenium after chronic exposure Re-exposure of mallards to selenium after chronic exposure

Adult male mallards (Anas platyrhynchos) were fed a control diet or a diet containing 15 ppm selenium as seleno-D,L-methionine for 21 weeks. After this initial exposure, the mallards were fed untreated food for 12 weeks, then were re-exposed to selenium at 100 ppm for five weeks. During re-exposure to 100 ppm selenium, the birds that had previously been exposed to 15 ppm selenium and...
Authors
G. H. Heinz
Was this page helpful?