Nest desertion by the pinyon jay (original) (raw)

Short Communications TABLE 2. Weight changes (g) of 11 Screech Owls between spring and fall-winter. [Auk, Vol. 96 Spring Fall-winter Sex Date captured (weight) Date captured (weight) Wt. gain Male 05-14-75 (150) 10-29-75 (180) +30 Male 04-15-76 (145) 10-30-75 (180) +35 Male 05-18-78 (170) 12-28-77 (185) + 15 Male 04-24-75 (160) 02-22-77 (165) +5 Male 05-04-76 (185) 02-22-77 (150) a-35 Female 05-11-78 (205) 12-05-78 (225) + 20 Female 05-14-76 (160) 12-28-77 (200) +40 Female 05-22-75 (190) 02-21-77 (220) +30 Female 04-24-76 (180) 02-21-77 (190) + 10 Female 05-04-76 (180) 02-22-77 (185) +5 Unknown 05-06-76 (205) 01-01-75 (220) + 15 Mean males 156.2 177.5 +21.3 Mean females 183.0 204.0 + 21.0 a Banded as adult on i May 1967, was at least 103A yr old and in poor condition; excluded from mean for males. the extremely cold winter of 1977-78, which included deep snow, five dead Screech Owls were found. No dead owls were found in 1975-76 or 1976-77 when the boxes were checked in the spring. Eighteen and 15 pairs nested successfully in the 150 nest boxes in 1976 and 1977, respectively. The number declined to 6 in 1978 (6 in 150 boxes, or 4%) following the severe winter; this is the lowest percentage recorded since the study began in 1944 (VanCamp and Henny 1975). It appears that a fall weight gain is important to the Screech Owl, but in spite of the weight gain, extreme weather conditions, which tend to occur irregularly, can still pose a hardship for this species near the northern edge of its breeding range in Ohio. The manuscript was improved by the reviews of Vivian M. Mendenhall and Anne R. McLane. LITERATURE CITED EARHART, C. M., & N. K. JOHNSON. 1970. Size dimorphism and food habits of North American owls.