Silvicultural prescriptions to enhance northern flying squirrel (Glaucoinys sabrinus) habitat have been suggested as an aid for recovery of the threatened northern spotted owl (Strix occidentalis caurina). Flying squirrels are hypothesized to be limited by den sites (cavities in trees) and by food (truffles). However, no quantitative information exists on den sites of flying squirrels. Therefore, during 1986-94, we used radiotelemetry to locate 604 different den sites in the southern Coast Range of Oregon, the southern Olympic Peninsula, and the Puget Trough of Washington. Den sites included cavities in live and dead old-growth trees; cavities, stick nests, and moss nests in small (10-50 cm dbh) second-growth trees; dens in cavities in branches of fallen trees; and dens in decayed stumps of oldgrowth trees and suppressed young trees. Two-thirds of all dens located were in live trees. Most dens were located during a study of second-growth forests in the Puget Trough. Females selected cavities for maternal dens. Squirrels used multiple dens; denning partners varied with den. Dens of males were 211 ± 7 m apart; dens of females were 108 ± 4 m apart. Males used 2.2 ± 0.1 dens per month; females 2.3 ± 0.1 dens per month. Dens, except maternal dens, were often occupied simultaneously by several adult squirrels. Many fragile den sites were used by females. Secure cavities are scarce and may limit reproductive success. Management for cavity trees and dens could prove fruitful in owl recovery and habitat restoration efforts.
Northern bobwhite, Colinus virginianus, were orally dosed with the organophosphorus insecticide chlorpyrifos to examine effects on brain chohnesterase (ChE) activity. Two‐week‐old quail were acutely exposed and euthanized at selected times following gavage‐dosing, ranging from I to 120 h later. The ChE activity was determined in treated birds and compared to concurrently tested control (corn oil) birds. It was found that a lag time of 2 to 4 h following exposure was necessary to detect significant ChE depression caused by chlorpyrifos. The lowest dose that produced ChE depression in these tests was between —30 and 50 mg chlorpyrifos/kg body weight, with some mortality occurring at the high end of that range. Depression typically persisted for at least 24 h.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.