Sexual dimorphism in northern spotted owls (Strix occidentalis caurina) from northwest California
Year: 1990
Type: article
Abstract: We measured weight, wing length, tail length, bill length, bill depth, and tarsus length and counted the number of complete tail bars of live adult and subadult Northern Spotted Owls (Strix occidentalis caurina).All variables showed significant differences between mean values for females and males (n = 65 females, 68 males).There was no significant correlation between male and female sizes of mated Spotted Owl pairs for any measurement variable (n = 64 pairs; 57 females and 56 males).We determined that weight was a better predictor of sex than the number of complete tail bars or any other measurement variable.Adding additional variables to weight in a discriminant analysis did not improve the original correct classification rate of 90.2%.Mean weights of female and male owls were 663 g ñ 42.8 (SD) and 579 g ñ 34.9, respectively.Dimorphism Indices were highest for the cube root of weight (4.51), tail length (3.30) and wing length (2.47).Determining sex of an owl in the field by the owl's vocalizations and behavior remains the most reliable sexing technique.Field measurements may be used to estimate the sex of a captured owl when behavioral cues are not available.
Language: English
Topic: Avian ecology and behavior
Subfield: Ecology
Field: Environmental Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W2946555255