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Once, these nests mainly clung to California\u2019s natural rocky cliffsides. But undeterred by human development, cliff swallows now often find their perfect spot on the underhang of a bridge or the eaves of a building\u00a0\u2014 meaning it\u2019s hard to avoid these migratory birds while they\u2019re in town.<\/p>\n
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April is the perfect time to see them as they architect their nests and get ready to lay eggs, said Murray Berner, a longtime field trip leader with the Audubon Society who\u2019s co-written several bird atlases for Napa and Solano counties.<\/p>\n
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Cliff swallows make mud nests under bridges each spring. This is a close-up of the underside of the Third Street Bridge in Napa.<\/p>\n
Bront\u00eb Wittpenn\/S.F. Chronicle<\/p>\n
The birds arrive in early March and begin building nests in April. Once laid, cliff swallow eggs take about two weeks to hatch, after which the nestlings will stay in the nest for about 23 days. The adult swallows will raise anywhere from one to three broods of young before wrapping up in late July, according to\u00a0Berner. They\u2019ll be gone by September, headed back to South America for the winter.<\/p>\n
A few key factors make for the perfect nesting ground: a 90-degree overhang, a textured surface and a nearby source of mud. Several cement bridges in California meet this criteria, but there are a few particularly well-known for cliff swallow nesting, including the Third Street Bridge in downtown Napa and Maxwell Bridge to the south,\u00a0Berner said.<\/p>\n
He recommended Napa\u2019s Veterans Memorial Park, which sits just along the river and underneath the Third Street Bridge, as a good location to spot the swallows.<\/p>\n
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A row of mud nests made by swallows can be seen as a gondola passes under the Third Street Bridge in Napa.<\/p>\n
Bront\u00eb Wittpenn\/S.F. Chronicle<\/p>\n
\u201cLook closely at the mud,\u201d Berner advised. Once you spot a group of mud-collecting birds, you can follow their path back to the bridge in order to watch the nest-building in action.<\/p>\n
Not every bird you spot will be a cliff swallow. House sparrows like to squat in cliff\u00a0swallow nests when they\u2019re away, and white-throated swifts also occasionally nest in crevices and holes on bridges, Berner said.<\/p>\n
Cliff swallows nest across the state. In 1930, Father St. John O\u2019Sullivan, pastor of Mission San Juan Capistrano near Laguna Beach (Orange County), recorded the swallows\u2019 behavior in the book \u201cCapistrano Nights.\u201d Sometimes they would chip away at the crumbling adobe walls of the mission in order to source building material for their nests, O\u2019Sullivan wrote. One of the mission\u2019s residents claimed the birds would cease building their nests on Sundays to observe a day of rest.\u00a0<\/p>\n
O\u2019Sullivan noted that the cliff swallows\u2019 arrival seemed to regularly coincide with the feast day of St. Joseph, March 19. Today, Mission San Juan Capistrano celebrates March 19 as both St. Joseph\u2019s Day and the Return of the Swallows with live performances and educational lectures.<\/p>\n
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A male house sparrow can be seen near a row of mud nests under the Third Street Bridge in Napa on April 15.<\/p>\n
Bront\u00eb Wittpenn\/S.F. Chronicle<\/p>\n
Cliff swallows are one of the rare species of birds whose population has grown even as human development has covered up the cliffs where they once nested,\u00a0Berner noted. The International Union for Conservation of Nature classifies the swallows as a species of least concern of extinction.<\/p>\n
And so Californians for decades to come can continue to admire the cliff swallows\u2019 unique nest building and listen out for the \u201cunmistakable squeaking cry\u201d that O\u2019Sullivan documented nearly a century ago.<\/p>\n","protected":false},"excerpt":{"rendered":"A pair of cliff swallows bring food to\u00a0hatchlings hidden in a mud nest beneath a bridge in Oceanside…\n","protected":false},"author":2,"featured_media":285460,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[6],"tags":[7,9,8,643,1727],"class_list":{"0":"post-285459","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-california","8":"tag-california","9":"tag-california-headlines","10":"tag-california-news","11":"tag-environment","12":"tag-outdoors"},"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/us-ca\/wp-json\/wp\/v2\/posts\/285459","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/us-ca\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/us-ca\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us-ca\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us-ca\/wp-json\/wp\/v2\/comments?post=285459"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/us-ca\/wp-json\/wp\/v2\/posts\/285459\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us-ca\/wp-json\/wp\/v2\/media\/285460"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/us-ca\/wp-json\/wp\/v2\/media?parent=285459"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/us-ca\/wp-json\/wp\/v2\/categories?post=285459"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/us-ca\/wp-json\/wp\/v2\/tags?post=285459"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}