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During the winter of 2005–2006, a large number of Snowy Owls (Bubo scandiacus) migrated to northwestern Montana. At least 42 owls were recorded in the Mission and Flathead Valleys. In one field of approximately 500 m2, 31 to 35 Snowy Owls roosted by day. Many owls roosted communally, and several age classes and both sexes were observed. No evidence of starvation or mortality was detected. This irruption migration was also noted throughout the Pacific Northwest.
Chestnut-backed Chickadees were studied over a 4-y period near Portland, Oregon, and for 1 of those years near Eugene, Oregon. Data on nesting activities and nestling growth rates were obtained by monitoring nest boxes. The chickadees began nest-building activity in March, with the 1st eggs being laid in early April and nests continuing to be initiated through early July. The timing of nest initiation was bimodal with the 1st peak in late April and a 2nd, smaller peak in June, referred to as “late nests”. Late nests accounted for 14 of the 94 nests observed. Clutch size for early nests varied from 5 to 10 eggs, with 7- and 8-egg clutches occurring at nearly equal frequency and representing 67.9%. Fledge success was greatest for 9-egg clutches and lowest for the smallest (6 or fewer) and largest (10) clutch sizes. Incubation averaged 13.8 d. The nestling growth phase averaged 18.8 d. Nestling body mass at age 14 d (the growth asymptote) was not correlated with clutch size or 14-d brood size. Late nests had lower clutch sizes but did not appear to be different for other reproductive parameters. Twenty-two nests failed to fledge any young at all, of which 13 nests failed due to predation. Predation by weasels was observed in one case and implicated in others. Other possible nest predators were Raccoons, Domestic Cats, and Douglas' Squirrels. Eviction of the chickadees by House Sparrows, House Wrens, and Bewick's Wrens was also observed.
The Night Snake (Hypsiglena torquata) is a secretive snake that is rarely encountered. Subsequently, little is known about the ecology of this species. Since it was first collected in 1943 in Washington State, few (<40) specimens have been found. From May to October 2004 and 2005, I collected 121 specimens from 8 counties in eastern Washington State by road-cruising appropriate habitat. Snakes were collected crossing roads bisecting a variety of habitats including areas of talus (such as rocky canyons), oak savannah-woodlands, sagebrush-rabbitbrush flats, pine-fir forests, grasslands, and areas of agricultural development (cropland). Snakes were most often observed in areas with an abundance of talus, followed by oak savannah-woodlands, sagebrush-rabbitbrush flats, and to a much lesser extent pine-fir forests, grasslands, and croplands. Based upon my research, H. torquata is much more common in Washington than previous work has shown.
Capture rates of 3 trap types were compared at 5 sites in and around Portland, Oregon, USA: Sherman traps, custom-made steel-mesh traps, and pitfall traps. Simpson and Shannon diversity indices were calculated for various combinations of trap types and compared for differences. Sherman and mesh traps also were evaluated for mortality rates before and after the use of a rain shield during the rainy winter months. Of the 5 species of small mammals caught in all 3 types of traps, pitfalls were the most effective trap, followed by Sherman traps, with mesh traps a very distant third. Sherman traps significantly outperformed mesh traps overall when compared for larger species that were not contained by pitfall traps. Different combinations of trap types yielded significantly different Simpson and Shannon diversity indices, with pitfalls having the highest measures for small mammals, and a combination of Sherman and pitfall traps having the highest measures when considering both larger and smaller mammals. Use of rain shields with Sherman and mesh traps did not affect mortality rates. However, mortality was affected by trap type, with significantly higher death rates in mesh than Sherman traps.