Population demographics of marbled murrelets (Brachyramphus marmoratus) are difficult to measure. Population size can be estimated from at-sea densities, and productivity indices are sometimes derived from ratios of hatch-year to after-hatch-year birds observed during systematic surveys on the ocean. However, one cannot determine from marine surveys alone what proportion of a marbled murrelet population sampled at sea is nesting in any given year, which would allow a more meaningful interpretation of productivity ratios. We hypothesized that group size (the number of murrelets occurring together on the water) could provide such an index if it could be demonstrated that single murrelets detected on the ocean during the incubation phase of the breeding season represent breeding birds. We monitored radio-tagged murrelets in Desolation Sound, British Columbia, from 29 May through 19 June 2001, using an incubating pair's distinct 24-h on-off occurrence on the water to determine nesting status. Of 160 murrelet groups comprised of at least 1 individual of known nesting status, there was a significantly greater percentage (37%) of single birds among incubating murrelets than among non-incubating birds (20%). Annual variation in the proportion of single murrelets recorded on marine surveys in Puget Sound during peak incubation corresponded with the annual productivity index in 4 of 5 y from 1997 to 2001. Our results suggest that group size, especially the proportion of single-bird groups, may help assess the proportion of murrelets that are nesting. Multiple-year comparisons of group size with nesting rates are needed to validate and interpret these results, and we need to continue to explore new methods to measure murrelet productivity.

We studied wintering owl use of hybrid poplar plantations, cropland, and shrub-steppe in northeastern Oregon. Logistic regression was used to identify habitat variables that best predicted owl presence or absence. We made 75 observations of 6 owl species during 2 y. The logistic regression model included the interiors of 5- and 6-y-old plantations as the best predictors of owl presence. Shrub-steppe habitat was included as the best predictor of owl absence. Significantly more owls were detected in 1999 compared to 2000. Maintaining an older component of interior plantation habitat within a plantation complex will likely create suitable wintering habitat for the owl species we studied.

Movement and cropping rate influences forage selectivity of deer. Previously, I found that male and female black-tailed deer (Odocoileus hemionus columbianus) had similar cropping rates on acorns. Herein, I tested whether movement rates differed between the sexes when deer fed on acorns. I detected a relationship between movement rate and acorn abundance but no intersexual differences in movement. Male and female deer foraged on acorns in a similar manner because they had similar movement and cropping rates.

We evaluated marking and radiotelemetry techniques of Oregon spotted frogs (Rana pretiosa) from October, 1996, through December, 2000, at Dempsey Creek, Thurston County, Washington. Knee tags (plastic, numerically-coded fingerling tags tied at the knee) and PIT tags (passive integrated transponders) were used to uniquely identify individuals. Transmitters weighing 1 to 1.8 g were attached to frogs using 5-mm wide nylon ribbon belts threaded through a tube at the anterior end of the transmitter. Four knee-tagged frogs exhibited skin and muscle lacerations and the technique was abandoned early in the study. PIT tags were expensive but proved to be convenient and reliable. The nylon ribbon transmitter attachment, applied 94 times, allowed us to monitor individual frogs for an average of 57 d but sometimes caused skin abrasions and had a 34% loss rate. We suggest ways to improve transmitter retention and prevent harm to frogs.