UNUSUAL RECORD OF BONAPARTE'S GULL IN THE SIERRA SAN PEDRO MARTIR, BAJA CALIFORNIA

摘要

On 11 December 2015, during a snowstorm, De León-Girón found a Bonaparte's Gull (Chroicocephalus philadelphia) unable to fly and at the point of starvation near the ranger office of the Sierra de San Pedro Mártir National Park. The location is 30° 59' N, 115° 33' 21' W, at an elevation of 2518 m, and the vegetation is coniferous forest dominated by Pinus jeffreyi (Delgadillo-Rodriguez 2004). The bird died two days later. The specimen, an adult male, was prepared and deposited at the Universidad Autónoma de Baja California (UABC 2072; Figure 1). The pectoral mass of the dissected specimen confirmed the starved condition of this individual when it was found in the park during the snowstorm. Measurements include total length 360 mm, wingspan 725 mm, tarsus 35 mm, wing length 237 mm, tail 106 mm, exposed culmen 29 mm, and mass 115 g, barely half the mean of 222 g reported for males by Burger and Gochfeld (2002).