Cliff swallow (Petrochelidon pyrrhonota) visits nest under a bridge in Crystal Peak Park, Verdi. July 28, 2015. Photo: K. Fitzgerald.
Cliff Swallows are very common along the Truckee River during summer months (see eBird database), and are often seen swooping and diving over the river channel hunting insects, or building mud nests under bridges.
Along the Truckee, Cliff Swallows could be confused with Tree Swallows, Violet-green Swallows, Northern Rough-winged Swallows, Bank Swallows or Barn Swallows. To identify a flying Cliff Swallow, look for a square patch of lighter-brown feathers above the tail. When they’re perched, look for a bright spot of white on the forehead .
In late April, Cliff Swallows return to the Truckee River region from their wintering grounds in South America. They form breeding pairs, and congregate around mud puddles and stream banks to collect mud, which they form into small pellets using their bills. They carry these pellets back to nest sites, one by one, and construct rounded mud nests on a vertical wall. When possible, they reduce the workload by sharing walls with neighbors — or even by stealing mud from neighboring nests (Beedy and Pandolfino 2013). Sometimes they will also repair or reuse existing nests (Ryser 1985).
Cliff Swallows nest in large colonies of up to 3,500 nests. Traditionally, Cliff Swallows nested on cliff faces in Western North America, but they have adapted well to the modern age and have expanded their range across the Great Plains and into Eastern North America by nesting under bridges, in culverts and on sides of buildings (Brown & Brown 1995).
Cliff swallows feed in groups over bodies of water, rapidly diving and turning to catch swarming insects. Males and females carry insects back to the nest to feed young, which generally fledge (learn to fly) by late July or early August.
By early fall, swallows desert their mud nests and begin the long journey to their wintering grounds. In parts of the Great Basin, other species of bird such as Rosy Finches and Canyon Wrens have been observed taking shelter in abandoned Cliff Swallow nests during the winter (Ryser 1985). If you see evidence of something similar along the Truckee, please submit an observation!
Beedy, Edward C. and Pandolfino, Edward R. 2013. Birds of the Sierra Nevada. Berkeley: University of California Press.
Brown, Charles R. and Mary B. Brown. 1995. Cliff Swallow (Petrochelidon pyrrhonota), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America Online: http://0-bna.birds.cornell.edu.innopac.library.unr.edu/bna/species/149 doi:10.2173/bna.149
Ryser, Fred A. 1985. Birds of the Great Basin. Reno: University of Nevada Press.