On 11 December 2015, during a snowstorm, De León-Girón found a Bonaparte’s Gull (Chroicocephalus philadelphia) unable to fl and at the point of starvation near the ranger offi of the Sierra de San Pedro Mártir National Park. Th location is 30° 59′ N, 115° 33′ 21″ W, at an elevation of 2518 m, and the vegetation is coniferous forest dominated by Pinus jeffeyi (Delgadillo-Rodríguez 2004). Th bird died two days later. Th specimen, an adult male, was prepared and deposited at the Universidad Autónoma de Baja California (UABC 2072; Figure 1). Th pectoral mass of the dissected specimen confimed 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).