Birds of the Tzitzio Region, Michoacan, Mexico
Chester C. Lamb collected birds at a locality three miles north of Tzitzio, eastern Michoacan, Mexico. From July 13 to 30, 1951, Mr. Lamb and his assistant, and my wife, Dr. Betty S. Davis, and I, made a second collection at this locality. We camped within a hundred yards of Mr. Lamb' s 1939 campsite. The two collections total 310 specimens, all of which are now in the Moore Collection, Occidental College. Eighty-three species were recorded, of which seventy were collected. Eighteen miles by
... ighteen miles by road east of Morelia, Michoacbn, at a military outpost known as El Temescal, a road leaves the main highway to Mexico City and leads south to Huetamo, on the Michoacan-Guerrero boundary. The town of Tzitzio (Sitzio on some maps) is situated on this road, about ten miles by road south of the main highway to Mexico City. Our camp was located at the settlement of San Juan de 10s Llanos, on the Huetamo road, an estimated three miles airline north of Tzitzio. The altitude at San Juan was 6500 feet as registered on our altimeter. Many of the slopes and ridges in this area are covered with a second growth pine-oak forest, the pines being predominant. Much of this forest has been cleared away to make space for cultivated fields and grassy pastures. Isolated stands of pines and oaks scattered throughout the grassland indicate that the pine-oak forest was once continuous in this area. There has also been a heavy upward invasion of the leguminous thorn scrub vegetation of lower elevations. This scrub forms impenetrable thickets bordering roads and trails and breaking up the continuity of the grassland areas. Thickets of thorn scrub often occur in conjunction with small stands of oaks, leading to the formation of an association best referred to as oak-thorn scrub. The partial clearing of the original pine-oak forest, together with the invasion of thorn scrub from below, has led to an intermingling of vegetational associations in the vicinity of San Juan. The composition of the avifauna reflects this interdigitation of associations, and high and low altitude species of birds are found together in this region. Our collecting activities were carried out in the immediate vicinity of San Juan, and all the vegetational associations were investigated. Much time was spent on a steep, pineoak forested ridge running east and west about 300 yards south of camp. The ridge was an estimated three hundred feet high and ended in a steep escarpment at the western end, below which lay the road to Huetamo. In the following species accounts July records pertain to 1951 and August records to 1939. CoragyPs stratus. Black Vulture. These vultures were seen nearly every day. They were only slightly less common than Turkey Vultures. Cathartes aura. Turkey Vulture. These were seen every day. On most occasions they appeared in greater numbers than the Black Vultures but on at least one bccasion they were outnumbered by them. Accipiter coop&. Cooper Hawk. On July 28 one bird circled high over camp. Accipiter striutus suttoni. Sharp-shinned Hawk. 13, IQ, August 5, 10. Both specimens are immature. Their large size (wing, $ , 181 mm., 0, 212 mm.), brick red underparts, and virtually immaculate thighs place them in suttoni. Buteo jamaicensis. Red-tailed Hawk. One individual was seen on July 13. Buteo brathyurus. Short-tailed Hawk. 1 9, July 16. On July 14 a small, white-bellied Buteo flew rapidly over the tops of the pines on the ridge south of camp, giving a clear, two-syllabled whistle. On July 16 a small, dark Buteo flew to a pine near where the first bird had been seen and perched, giving the same whistled call as that previously noted. This individual, a melanistic juvenal Shorttailed Hawk, was collected. The crop and stomach contained the remains of a small bird. The hawk noted on July 14 was presumably an adult or juvenile of this species in the white-bellied phase. Mar., 1953 BIRDS OF TZITZIO, MICHOACAN 91 Aquila chrysudtos. Golden Eagle. On July 28 my wife and I noted a huge hawk circling with an estimated 15 Black and 10 Turkey vultures. Closer inspection, using 9 power binoculars, revealed an immature eagle. The prominent white wing patches and white tail edged and bordered terminally with black were seen clearly. A short time later two adults came into view. The reddish gleam of their hindnecks and their huge hooked bills were readily visible. The three birds dwarfed even the Turkey Vultures. They were superb fliers, describing great circles in effortless fashion. Vultures of both species gave them a wide berth. The adults were silent but the immature uttered an occasional plaintive whistled call. As we were about to leave a second immature dove in with partly folded wings. The group of four then circled out of sight. Some time later, from a distance of about a mile, an immature was seen still circling with the vultures. The Golden Eagle has never before been recorded from Michoacan, although specimens have been taken near Irapuato, Guanajuato, some 80 miles north of Tzitzio. , Herpetotheres cacchinans. Laughing Falcon. This species was heard several times. On July 26 Mr. Lamb saw one fly into a tree near camp. Philortyr faxtitus. Barred Quail. Large coveys of these quail were flushed on several occasions but they invariably settled in dense thorn scrub and none was collected. Colinus virginiunzcs. Bob-white. A pair was flushed twice from heavy oak-thorn scrub vegetation bordering a grassy field on July 13 and 25. Scardufella inca. Inca Dove. I$ , 19, July 23. Inca Doves were common in thorn scrub and were seen or heard many times. Piayu cayana mexicana. Squirrel Cuckoo.