Diet and Foraging

Forages mostly on the ground in rocky habitats, frequenting the bases of shrubs, rock crevices, and caves. Gleans prey from crevices and rocky surfaces, including vertical rock walls. Diet includes spiders, insects, and other arthropods.

Microhabitat for Foraging

In Arizona, 70% of foraging time was spent in secluded or covered situations on exposed cliffs and walls (1 Tramontano, J. P. (1964). Comparative studies of the Rock Wren and the Canyon Wren. M.S. thesis, University of Arizona, Tucson, AZ, USA. Close ); birds in southern California foraged 67.5% under rocks and 18.3% in rock crevices (2 Mirsky, E. N. (1976). Ecology of coexistence in a wren-wrentit-warbler guild. Ph.D. dissertation, University of California, Los Angeles, CA, USA. Close ). In northern Colorado, 48% of foraging was in cliff crevices and cavities, 39% in talus and boulders, and 13% on vegetation or open ground (69 Warning, N., and L. Benedict (2015). Overlapping home ranges and microhabitat partitioning among Canyon Wrens (Catherpes mexicanus) and Rock Wrens (Salpinctes obsoletus). Wilson Journal of Ornithology 127:395–401. Close ). No seasonal shifts in foraging microsites were observed (2 Mirsky, E. N. (1976). Ecology of coexistence in a wren-wrentit-warbler guild. Ph.D. dissertation, University of California, Los Angeles, CA, USA. Close , SLJ, JSD). Within territories, foraging was generally restricted to areas having vertical cliffs and large piles of boulders (57 Grinnell, J., and A. H. Miller (1944). The distribution of birds of California. Pacific Coast Avifauna 27:1–608. Close , 22 Bent, A. C. (1948). Life histories of North American nuthatches, wrens, thrashers, and their allies. United States National Museum Bulletin 195. Close , 1 Tramontano, J. P. (1964). Comparative studies of the Rock Wren and the Canyon Wren. M.S. thesis, University of Arizona, Tucson, AZ, USA. Close , 2 Mirsky, E. N. (1976). Ecology of coexistence in a wren-wrentit-warbler guild. Ph.D. dissertation, University of California, Los Angeles, CA, USA. Close , SLJ, JSD), but was occasionally observed foraging on the ground, in vegetation (1 Tramontano, J. P. (1964). Comparative studies of the Rock Wren and the Canyon Wren. M.S. thesis, University of Arizona, Tucson, AZ, USA. Close , 70 Warning, N. B. (2014). Canyon Wren and Rock Wren coexistence in the northern Colorado foothills. M.S. thesis, University of Northern Colorado, Greeley, CO, USA. Close ), on tree trunks, and in Cliff Swallow (Petrochelidon pyrrhonota) nests (5 Warning, N., N. Covy, A. Rose, X. M. Phan, and L. Benedict (2015). Canyon wren territory occupancy and site attributes in northern Colorado. American Midland Naturalist 174:150–160. Close ).

Food Capture and Consumption

Gleans spiders, insects, and other arthropods from rocky surfaces and crevices, often in concealed situations (Figure 2) (57 Grinnell, J., and A. H. Miller (1944). The distribution of birds of California. Pacific Coast Avifauna 27:1–608. Close , 22 Bent, A. C. (1948). Life histories of North American nuthatches, wrens, thrashers, and their allies. United States National Museum Bulletin 195. Close ). Occasionally attempts flycatching (1 Tramontano, J. P. (1964). Comparative studies of the Rock Wren and the Canyon Wren. M.S. thesis, University of Arizona, Tucson, AZ, USA. Close , SLJ). Observed removing cached spiders from trypoxylid wasp nests (71 Martin, R. F. (1971). The Cañon Wren (Catherpes mexicanus) raiding food storage of a trypoxylid wasp. Auk 88(3):677. Close ).

Adaptations for Foraging

The Canyon Wren has several morphological adaptations for foraging in rock crevices and interstitial spaces: its bill is long and slender and its cranium is dorsoventrally flattened, enabling this species to probe deeply into narrow crevices (Figure 2). Short tarsi facilitate foraging under rocks by lowering the bird's height at the shoulders without affecting locomotion (2 Mirsky, E. N. (1976). Ecology of coexistence in a wren-wrentit-warbler guild. Ph.D. dissertation, University of California, Los Angeles, CA, USA. Close ).

In addition, the attachment of vertebral column to the braincase is modified (2 Mirsky, E. N. (1976). Ecology of coexistence in a wren-wrentit-warbler guild. Ph.D. dissertation, University of California, Los Angeles, CA, USA. Close ). The occipital region and foramen magnum are attached higher on the braincase, thus lowering the height of the braincase when the bird's head is extended horizontally. This alters the foraging thrust, making it directly forward rather than down and forward, possibly allowing the bird to reach more deeply into crevices (2 Mirsky, E. N. (1976). Ecology of coexistence in a wren-wrentit-warbler guild. Ph.D. dissertation, University of California, Los Angeles, CA, USA. Close ). Sexual size dimorphism in bill structure suggests different foraging microhabitats between the sexes (2 Mirsky, E. N. (1976). Ecology of coexistence in a wren-wrentit-warbler guild. Ph.D. dissertation, University of California, Los Angeles, CA, USA. Close ).

Major Food Items

The Canyon Wren is primarily insectivorous (22 Bent, A. C. (1948). Life histories of North American nuthatches, wrens, thrashers, and their allies. United States National Museum Bulletin 195. Close , 58 Miller, A. H., and R. C. Stebbins (1964). The lives of desert animals in Joshua Tree National Monument. University of California Press, Berkeley, CA, USA . Close ). Opportunistic, it eats locally abundant terrestrial invertebrates, including spiders, ants, beetles, centipedes, crickets, flies, grasshoppers, leafhoppers, moths, and termites (1 Tramontano, J. P. (1964). Comparative studies of the Rock Wren and the Canyon Wren. M.S. thesis, University of Arizona, Tucson, AZ, USA. Close , 72 Warning, N., and D. Leatherman (2016). Observations of Canyon Wren nestling diet during prey delivery. Natural Areas Journal 36:181–186. Close ). See Table 2 for a list of prey items documented.

Quantitative Analysis

The composition of its diet, from a study in Molino Canyon, Arizona (percent occurrence, n = 7), included Arachnida (Lycosidae, Phalangodidae) 10%; Lepidoptera (Noctuidae) 4%; Coleoptera (Apionidae, Gyrinidae, Scarabaeidae, Tenebrionidae) 9%; Dermaptera 1%; Hemiptera (Pentatomidae, Reduviidae) 1%; Membracoidea (Cicadellidae, Cicadidae) 12%; Hymenoptera (Formicidae) 17%; Blattodea (Kalotermitidae) 26%; Neuroptera (Myrmeleontidae) 8%; Orthoptera (Acrididae) 2%; Mantodea (Mantidae) 1%; and unknown 9% (1 Tramontano, J. P. (1964). Comparative studies of the Rock Wren and the Canyon Wren. M.S. thesis, University of Arizona, Tucson, AZ, USA. Close ). Prey size ranged from 2–12 mm (1 Tramontano, J. P. (1964). Comparative studies of the Rock Wren and the Canyon Wren. M.S. thesis, University of Arizona, Tucson, AZ, USA. Close ).

A northern Colorado study of prey delivery to nestlings (percent occurrence, n = 4 nests) included these orders: Lepidoptera (moths, 21%); Orthoptera (grasshoppers and crickets, 16%); Arachnida (spiders, 11%); Diptera (flies, 10%); Scutigeromorpha (house centipedes; 8%); Coleoptera (beetles, 5%); Hemiptera (true bugs, 2%); Isopoda (isopods, 1%); Hymenoptera (ants, bees and wasps, 1%); Lithobiomorpha (stone centipedes, 1%); and unidentified (25%) (72 Warning, N., and D. Leatherman (2016). Observations of Canyon Wren nestling diet during prey delivery. Natural Areas Journal 36:181–186. Close ). Observations of foraging by Canyon Wrens that nested in former Cliff Swallow nests, suggest that swallow bugs (Oeciacus vicarious) may be part of the diet (5 Warning, N., N. Covy, A. Rose, X. M. Phan, and L. Benedict (2015). Canyon wren territory occupancy and site attributes in northern Colorado. American Midland Naturalist 174:150–160. Close ).

The Rock Wren (Salpinctes obsoletus) has a similar diet, consisting mainly of grasshoppers, crickets, spiders, beetles, and other insects (22 Bent, A. C. (1948). Life histories of North American nuthatches, wrens, thrashers, and their allies. United States National Museum Bulletin 195. Close , 1 Tramontano, J. P. (1964). Comparative studies of the Rock Wren and the Canyon Wren. M.S. thesis, University of Arizona, Tucson, AZ, USA. Close , 73 Pitt, S. M. G. (2018). Why sing so many songs? Testing the function of song type repertoires in Rock Wrens using playback experiments and behavioral observations. M.S. thesis, University of Northern Colorado, Greeley, CO, USA. Close ), but usually forages in different microhabitats (69 Warning, N., and L. Benedict (2015). Overlapping home ranges and microhabitat partitioning among Canyon Wrens (Catherpes mexicanus) and Rock Wrens (Salpinctes obsoletus). Wilson Journal of Ornithology 127:395–401. Close ).

Information needed.

Information needed.

Information needed.

Likely relies largely on metabolic water production and water from insect prey. Many individuals are closely associated with water in canyons, while others live in arid deserts without access to water. Has been seen foraging on sides of desert springs, rivers, and reservoirs without evidence of drinking (74 Smyth, M., and H. N. Coulombe (1971). Notes on the use of desert springs by birds in California. Condor 73:240–243. Close , 5 Warning, N., N. Covy, A. Rose, X. M. Phan, and L. Benedict (2015). Canyon wren territory occupancy and site attributes in northern Colorado. American Midland Naturalist 174:150–160. Close ); the image below is suggestive of drinking free water, but details are lacking.

Pellet-casting not documented.