Canyon Wren Catherpes mexicanus Scientific name definitions

Stephanie L. Jones, Joseph Scott Dieni, Nathanial B. Warning, David Leatherman, Lorraine Dargis, and Lauryn Benedict
Version: 2.0 — Published January 6, 2023

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); birds in southern California foraged 67.5% under rocks and 18.3% in rock crevices (2). 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). No seasonal shifts in foraging microsites were observed (2, SLJ, JSD). Within territories, foraging was generally restricted to areas having vertical cliffs and large piles of boulders (57, 22, 1, 2, SLJ, JSD), but was occasionally observed foraging on the ground, in vegetation (1, 70), on tree trunks, and in Cliff Swallow (Petrochelidon pyrrhonota) nests (5).

Food Capture and Consumption

Gleans spiders, insects, and other arthropods from rocky surfaces and crevices, often in concealed situations (Figure 2) (57, 22). Occasionally attempts flycatching (1, SLJ). Observed removing cached spiders from trypoxylid wasp nests (71).

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).

In addition, the attachment of vertebral column to the braincase is modified (2). 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). Sexual size dimorphism in bill structure suggests different foraging microhabitats between the sexes (2).


Major Food Items

The Canyon Wren is primarily insectivorous (22, 58). Opportunistic, it eats locally abundant terrestrial invertebrates, including spiders, ants, beetles, centipedes, crickets, flies, grasshoppers, leafhoppers, moths, and termites (1, 72). 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). Prey size ranged from 2–12 mm (1).

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). 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).

The Rock Wren (Salpinctes obsoletus) has a similar diet, consisting mainly of grasshoppers, crickets, spiders, beetles, and other insects (22, 1, 73), but usually forages in different microhabitats (69).

Food Selection and Storage

Information needed.

Nutrition and Energetics

Information needed.

Metabolism and Temperature Regulation

Information needed.

Drinking, Pellet-Casting, and Defecation

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, 5); the image below is suggestive of drinking free water, but details are lacking.

Pellet-casting not documented.

Recommended Citation

Jones, S. L., J. S. Dieni, N. B. Warning, D. Leatherman, L. Dargis, and L. Benedict (2023). Canyon Wren (Catherpes mexicanus), version 2.0. In Birds of the World (P. G. Rodewald, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.canwre.02