THE CONDOR VOLUME 58 MARCH-APRIL, 1956 NUMBER 2 SUMMER BIRDS OF THE RINCON MOUNTAINS, SAGUARO NATIONAL MONUMENT, ARIZONA By JOE T. MARSHALL, JR. The Rincon Mountains, situated within the Saguaro National Monument just east of Tucson, Arizona, richly merit the attention of those eager to see and understand natural environments in the southwest. These mountains harbor numerous species of Mexican birds responsible for the intense interest of several generations of ornitholo- gists in the neighboring mountains of extreme southern Arizona. They support a varied and beautiful woodland at middle altitudes which differs radically from monotonous stretches of pinyon, juniper, and chaparral at the same level farther north. Trees such as the Chihuahua pine, blue oak, Arizona oak, silver-leaf oak, and Arizona madrone, widely distributed in Mexico, are conspicuous in this woodland, which flourishes next to a boreal forest of majestic proportions. Further, the Rincons contain these contrast- ing floras and their avifaunas within a moderate-sized area. An hour’s walk from a cen- tral location, such as Manning Camp, takes one into any of several natural environ- ments, each so different that it is like stepping into a new world. Above the lower limit of oaks, there are about 89 square miles of wooded heights in the Rincons, twenty square miles of which are coniferous forest. Woodland and forest are isolated by desert from the Santa Rita Mountains which lie thirty miles directly south, and they are separated by low hills supporting only scattered oaks in gullies from the Santa Catalina Moun- tains twelve miles to the northwest. Mica Mountain, which alone is considered here, lies in the northern part of the Rincons and is of mild relief. The summit area, the highest point of which is 8600 feet above sea level, contains rolling hills and broad drainage basins. Its south slope is of gentle descent; a long ridge inclines to the west; the northwest slope is steep; a barren rocky ridge occupies the northeast corner; and the east end of -the elevated forest is bounded by a great cliff, beneath which the land slopesto Happy Valley at the east base of the mountain. Vegetation adorns this uncomplicated topography with a simplicity unique in southeastern Arizona; and contrasting vegetation types meet at the angles of the mountain with rather abrupt transitions. On either side of such a boundary one can determine from the different numbers of a given bird specieswhat it must be choos- ing for its habitat. Accordingly my purpose, in addition to reporting on variation in House Wrens (a study which first took me to the Rincons), is to represent the relation of breeding birds to vegetation (fig. 1) and to mention unique features of plant and bird life in that portion of the mountain above the desert foothills. The report is based on my notebook entries made on visits on January 20 and 21, 1951, from May 30 to June 11, 1954, and on April 29 and 30, 1955. At least three collections from the Rincons represent most of the summer birds in museums (fig. 1). Herbert Brown, collecting at Manning Camp in July and August, 1911, mentioned in his notebook the grand scenery; Laurence M. Huey made a large collection from Spud Rock Ranger Station in June, 1932 ; and I took mostly House Wrens in the course of the visits reported here. I know of no published reference to birds of the Rincon Mountains other than the two follow- ing. Huey (1944) discussesa remarkable adult male hummingbird collected at Man- [ 81 1 82 THE CONDOR PTERIS AQUILINA PlyUS CEMBROIDES I AYACAHUITE I LEIOPHY LLA PONDEROSA PSEUDOTSUGA TAXI FOLIA ABIES CONCOLOR JUNIPERUS DEPPEANA MUHLENBERGIA NOLINA AGAVE SCHOTTI I POPULUS TREMULOIDES SALIX (THICKET) ALNUS OBLOGIFOLIA OUE$CUS RETICULATA ( SHRUB 1 ” OBLOGIFOLIA II ARIZONICA II GAMBELII II EMORYI HYPOLEUCOIDES PLATANUS VAUQUELINIA HOLODISCUS PRUNUS VIRENS ROBINEA NEOMEXICANA RHUS TRILOBATA ACER NEGUNDO RHAMNUS CALIFORNIGA CEANOTHUS FENDLERI ECHINOCEREUS TRIGLOCHI IIIATUS ARBUTUS ARIZONICA ARCTOSTAPHYLOS pu NGENS FR~XINUS VELUTINA SY MPHORICARPOS TURKEY VULTURE l COOPER HAWK RI PARIAN_ l RED-TAILED HAWK ZONE-TAILED HAWK 33zm PEREGRINE FALCON CLIFFS_ l BAN D-TAILED PIGEON WHITE-WINGED DOVE ROAD-RUNNER l (SCREECH OWL ) SPOTTED SCREECH OWL l SCOPS OWL ELF OWL SPOTTED OWL l WHIP-POOR-WILL POOR-W ILL WHITE-THROATED SWIFT CLIFFS_ BLACK-CHINNED HUMMINGBIRD . BROAD-TAILED HUMMINGBIRD Fig. 1. Occurrence of plants and birds according to types of vegetation or other environments inhabited. A bar ending abruptly at a boundary between plant formations indicates that the bird is to be expected beyond that boundary although it was not seen there. Mar., 1956 BIRDS OF THE RINCON MOUNTAINS WOODLAND 1 FOREST . RIVOLI HUMMINGBIRD . RED-SHAFTED FLICKER . ACORN WOODPECKER Happy Valley . HAIRY WOODPECKER LADDER-BACKED WOODPECKER ARIZONA WOODPECKER 8 ASH-THROATED FLYCATCHER BLACK PHOEBE stream gafge _ l WESTERN FLYCATCHER . (BUFF-BREASTED FLYCATCHER) . WESTERN WOOD PEWEE clearings,aspem_ . COUES PEWEE . VIOLET-GREEN SWALLOW snags_ . STELLER JAY SCRUB JAY manzonita chaparral_ ARIZONA JAY RAVEN . MOUNTAIN CHICKADEE . BRIDLED TITMOUSE . BUSH-TIT . WHITE-BREASTED NUTHATCH . PIGMY NUTHATCH . CREEPER . HOUSE WREN . BEWICK WREN CANYON WREN cliffs_ (ROCK WREN) racks CRISSAL THR& SHER monzanita-- . HERMIir THRUSH _ . MEXICAN BLUEBIRD . BLUE-GRAY GNATCATCHER HUTTON VIREO . SOLITARY VIREO . WARBLING VIREO - aspenwillows I r 1 . VIRGINIA WARBLER . OLIVE WARBLER . AUDUBON WARBLER . BLACK-THROATED GRAY WA ILER . GRACE WARBLER . RED-FACED WARBLER deciduous trees - . PAINTED REDSTART SCOTT ORIOLE WESTERN TANAGER . HEPATIC TANAGER . BLACK-HEADED GRO! . EVENING GROSBEAK I I I (HOUSE FINCH) open country_ PINE SISKIN ARKANSAS GOLDFINCH . RED-EYED TOWHEE RUFOUS-CROWNED SPARROW . YELLOW-EYED JUNG0 Fig. 1 (continued). A bar chopped off at left margin means that species continued down into desert. A bar at left of species name signifies specimens from Rincons extant in museums. 84 THE CONDOR Vol. 58 ning Camp in June. It is a hybrid between the Costa and Broad-tailed hummingbirds. The A.O.U. Check-list Committee (1950:369) includes the Rincon Mountains in the range of the Brown-throated Wren, Troglodytes brunneicollis, which was added as a species new to the check-list. In the following discussion, I propose to merge this wren with the House Wren, Troglodytes aifdon. ACKNOWLEDGEMENTS Superintendent John G. Lewis and his staff of the Saguaro National Monument made my trips possible. I am indebted also to William Fish for playing his recording of House Wren songs, to Laurence M. Huey for a copy of his field catalogue of the Rin- cons, and to the respective curators who facilitated my examination of specimens of Brown Creepers and House Wrens in the collections of A. R. Phillips, Saguaro National Monument, San Diego Society of Natural History, W. J. Sheffler, and the University of California at Los Angeles. ENtlNAL PIWON Fig. 2. Idealized arrangement of plant associations on the Rincon Mountains, looking north- ward. Symbols distinguish the aspen and each species of oak and conifer. FLORA Some of the plants important for the distribution of birds on the mountain are listed in figure 1. Ponderosa pine attains here its best de.velopment in southern Arizona, both in stature of individuals and extent of unbroken groves. (Most of these trees have needles in fives, but those of the isolated group at Grass Shack, 5300 feet, have needles in threes only.) Likewise Gambel oak and vauquelinia attain exceptionally large size in the‘ Rincons. During my visit, the most attractive and abundant flowers were the hedge- hog cactus, growing on the rocks, and the New Mexican locust, covering hillsides on the east slope with masses of blooms. Because of its intermediate position between neighboring mountains, Mica Mountain has no alpine fir, the southern limit of which Mar.. 1956 BIRDS OF THE RINCON MOUNTAINS 85 is in the Santa Catalina Mountains, and no Apache pine, a Mexican species which reaches the Santa Rita Mountains. These trees are relatively unimportant in those places and cannot account for differences in bird-life in the three mountains. Some plants are confined to a particular slope of Mica Mountain. White fir occurs only on the northwest face, where it extends upward to within about 200 yards of the crest. Douglas fir reaches this crest, and is likewise confined to the same slope, except for three individuals near Manning Camp. I found the New Mexican locust only on the east wall of the mountain. Aspen is also prevalent there; elsewhere I found it only in a gully near Manning Camp. From Tucson a large patch can be seen part way down the northwest slope. Arizona cypress is absent from the canyons I visited. VEGETATION In two respectsthe vegetation of Mica Mountain differs from that of the Santa Cata- lina Mountains (Shreve, 1915). First, each major plant grouping is “all in one piece” (fig. 2). All the fir forest is on the northwest slope; the ponderosa pine forest is con- tinuous over the broad summit; and woodland completely encircles the mountain be- tween forest and desert. There is little if any alternation of tracts of pine forest with fir forest or with woodland, or of woodland with desert such as is found on the Santa Catalinas, whose deep canyons support contrasting vegetations on opposite walls. Sec- ond, there is a remarkable difference between the east and west slopes of the mountain. On the west, the oak woodland, except on flood-plains, is dwarfed and includes as con- spicuous elements Pinus cembroides, Juniperus deppeana, Nolina microcarpa, Agave Fig. 3. Spud Rock Ranger Station, 7400 feet, an area of mixed vegetation. In foreground is a wet meadow of grass and sedge surrounded by tall bracken; farther to right, past a glade of silver-leaf oaks, is a hillside of New Mexican locust overlooked by an open grove of ponderosa pines with bunchgrass.