SECOND UNUSUAL RECORD OF COMMON LOON, GAVIA IMMER, FOR COAHUILA, MEXICO, AND ITS FIRST REPORT FOR THE CUATRO CIE ´ NEGAS BASIN ARMANDO J. CONTRERAS-BALDERAS* AND GORGONIO RUIZ-CAMPOS Laboratorio de Ornitologı´a, Facultad de Ciencias Biolo ´gicas, Universidad Auto ´noma de Nuevo Leo ´n, San Nicola ´ s de los Garza, Nuevo Leo ´n, 66450, Me ´xico (AJCB) Coleccio ´n Ornitolo ´gica, Facultad de Ciencias, Universidad Auto ´noma de Baja California, Ensenada, Baja California, 22800, Me ´xico (GRC) *Correspondent: arcontre@fcb.uanl.mx ABSTRACT—The common loon (Gavia immer) has occasionally been reported inland in northern Mexico. The first record in Coahuila, Mexico, was collected at El Tulillo reservoir in November 1986. The present record is more unusual, because it was collected on 12 June 2003, a late date for any location at this latitude. Damage caused by shotgun pellets to the ventral surface of both wings apparently prevented flight. This represents the second record for the state of Coahuila and the first record for the Cuatro Cie ´negas Valley. RESUMEN—El somorgujo comu ´n(Gavia immer) esta ´ reportado como ocasional en tierras interiores del norte de Me ´xico. El primer registro para el estado de Coahuila, Me ´xico, fue colectado en la Presa El Tulillo en noviembre de 1986. El presente reporte es ma ´s inusual, dado que fue colectado el 12 de junio del 2003, demasiado tardı ´o para cualquier a ´rea en esa latitud. El dan ˜o causado por los perdigones de escopeta a la parte ventral de ambas alas le impidio ´ volar. Este representa el segundo registro para el estado de Coahuila, y el primero para el Valle de Cuatro Cie ´negas. The valley of Cuatro Cie ´negas, Coahuila, Mexico, known worldwide for its endemic biota and as one of the most important protected natural areas in Mexico, continues to offer new avifaunal records as the study of faunal elements intensifies (Contreras-Balderas et al., 2004). To date, 155 species of birds have been documented in the region, 38% of which have been recorded during the last 15 y (e.g., Contreras-Balderas et al., 1997, 2004; Gonza ´lez-Rojas et al., 1999). During an ornithological survey in the valley of Cuatro Cie ´negas on 12 June 2003, a common loon (Gavia immer; Fig. 1) was found swimming slowly near the edge of Laguna Playitas (26u549360N, 102u009050W; elevation 700 m above sea level), a large pond with a depth .2 m and a sandy and rocky bottom. The water was blue and clear. The individual was captured manually by the lead author (AJCB) and later transported to the laboratory for examination and preparation. During the examination of the specimen, we found small injuries resulting from shotgun pellets on the ventral surface of both wings. This likely explains why we found this individual alive and alone in June. Food availability at the site probably allowed the survival of the individual until this date. We do not attribute this record to a range expansion for the species, but it is unusual and late for a migrant species (Howell and Webb, 1995; AOU, 1998). Our specimen was a juvenile with first summer plumage. The voucher specimen was cataloged and deposited in the bird collection of the Facultad de Ciencias Biolo ´ gicas, Universidad Auto ´ noma de Nuevo Leo ´ n (UANL-2441). The body measurements of this specimen and its comparison with other Pacific and common loons from northern Mexico are in Table 1. The common loon has a mainly Nearctic distribution, with a breeding range between 48uN and the Arctic Circle. In some places, they are found south to about 40uN, and north to about 78uN. In the north Atlantic, common loons also breed in Greenland, Iceland, and possibly Scotland (Carboneras, 1992). Its winter distribu- tion along the Pacific coast ranges from the Aleutian Islands to Baja California and Colima, Mexico; along the Atlantic and Gulf coasts, it is found from Newfoundland south to southern Florida and west to Tamaulipas (AOU, 1998). March 2007 Notes 153