The reproductive success of birds depends in large part on the location of the nest.\u00a0 A nest should provide protection from the elements.\u00a0 It should be well hidden to prevent its discovery by egg or nestling predators.<\/p>\n
Some bird species build their nests in the proximity of other species of birds. In today\u2019s column, we will explore some of these nesting associations and learn the advantages of such arrangements.<\/p>\n
This column was inspired by an observation that Bets Brown (my wife) and made on June 16.\u00a0 Bets was conducting a Breeding Bird Survey and I came along as her data recorder.\u00a0 At a stop in Monmouth, a pair of Ospreys had constructed a nest atop an electrical transformer tower.\u00a0 Bets saw a couple of small birds disappearing into and emerging from the bottom of the massive nest.\u00a0 Those birds were House Sparrows.\u00a0 What better place to place a nest?\u00a0 Potential predators of House Sparrow eggs or nestlings are likely to be deterred by the fearsome Ospreys.\u00a0 As strict fish-eaters, Ospreys pose little threat to the House Sparrows.<\/p>\n
A search of the literature revealed that House Sparrows have been reported nesting in Osprey nests in other areas.\u00a0 Monk Parakeets, which build spherical stick nests, have also been seen using Osprey nests as a site for their own nest construction.<\/p>\n
Although the pair of House Sparrows we saw likely benefitted from the association with Ospreys, we do not know if the House Sparrows particularly sought out the Ospreys or simply found the massive nests of the Ospreys to be a nice place to set up house.\u00a0 I suspect it was the latter.\u00a0 In any case, House Sparrows outnumber Ospreys by many orders of magnitude so a House Sparrow nest in an Osprey nest must be an exceptional event from the point of view of House Sparrows.<\/p>\n
However, nearly 100 bird species clearly prefer to nest in proximity to a more aggressive species.\u00a0 Most examples of protected associates are waterfowl, shorebirds and songbirds while the aggressive species sought out by the protected associate species are usually particularly aggressive shorebirds, falcons and sometimes stinging or biting insects.<\/p>\n
In Ontario, Yellow Warblers prefer to nest close to Gray Catbird or Red-winged Blackbird nests.\u00a0 Near Gray Catbirds, predation on the warbler nests is significantly reduced.\u00a0\u00a0 Brood parasitism by Brown-headed Cowbirds is greatly reduced in warbler nests near Red-winged Blackbird nests.\u00a0 The redwings aggressively keep cowbird females out of their territories.<\/p>\n
On Kent Island in the Bay of Fundy, Savannah Sparrows have two major nest predators: abundant but ineffective Herring Gulls and uncommon but ruthlessly effective American Crows.\u00a0 The sparrows choose to nest near the gulls because the gulls keep the crows away.\u00a0 The sparrows build their nests in dense microhabitats that the gulls avoid.<\/p>\n
In the Siberian arctic, more than 80% of Red-breasted Geese nest close to either Peregrine Falcon or Snowy Owl nests.\u00a0 Arctic Foxes are a major threat to goose eggs and goslings.\u00a0 In 454 hours of observations, no nest predation by foxes was observed for nests in the vicinity of owls or falcons.\u00a0 In fact, foxes only came within the defense area of the aggressive species twice and in both cases were quickly attacked.\u00a0 The foxes fled with their tails literally between their legs.<\/p>\n
In the Manitoba arctic, Long-tailed Ducks choose to nest near Arctic Tern nests.\u00a0 In some habitats, the ducks place their nests within three meters of the aggressive terns.<\/p>\n
We know at least one example where a protected associate has a negative influence on the aggressive species.\u00a0 In Peru, Black Skimmers and two species of terns nest on beaches along the Manu River.\u00a0 The terns and skimmers actively defend their nests against predators.\u00a0 Sand-colored Nighthawks nest among the skimmers and terns, often in numbers exceeding the aggressive species.\u00a0 The nighthawks never defend their nests, relying instead on the protection of the skimmers and terns.\u00a0 The nighthawks had greater nesting success in association with the other birds.\u00a0 However, their presence reduced the success of the terns and the skimmers because they spent more time in defense and less in parental care.\u00a0 The nighthawks are essentially parasitizing the terns and skimmers.<\/p>\n
Purple Finch project<\/strong><\/p>\n Sarah Knutie, a graduate student at the University of Utah, is beginning a long-term monitoring project of Purple Finches.\u00a0 She is soliciting volunteers who are willing to keep track of Purple Finch, House Finch and Pine Siskin abundance at their feeders from September through March.\u00a0 The time commitment is modest, only 1-2 hours a month.\u00a0 If you would like to help Sarah with her project, let her know of your interest by emailing her at purple.finches@gmail.com<\/a><\/p>\n [Originally published on June 26, 2010]<\/p>\n\n The reproductive success of birds depends in large part on the location of the nest.\u00a0 A nest should provide protection from the elements.\u00a0 It should be well hidden to prevent its discovery by egg or nestling predators. Some bird species build their nests in the proximity of other species of birds. In today\u2019s column, we […]<\/p>\n","protected":false},"author":146,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_s2mail":"","ngg_post_thumbnail":0,"footnotes":""},"categories":[1],"tags":[],"builder_content":"","_links":{"self":[{"href":"https:\/\/web.colby.edu\/mainebirds\/wp-json\/wp\/v2\/posts\/300"}],"collection":[{"href":"https:\/\/web.colby.edu\/mainebirds\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/web.colby.edu\/mainebirds\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/web.colby.edu\/mainebirds\/wp-json\/wp\/v2\/users\/146"}],"replies":[{"embeddable":true,"href":"https:\/\/web.colby.edu\/mainebirds\/wp-json\/wp\/v2\/comments?post=300"}],"version-history":[{"count":1,"href":"https:\/\/web.colby.edu\/mainebirds\/wp-json\/wp\/v2\/posts\/300\/revisions"}],"predecessor-version":[{"id":301,"href":"https:\/\/web.colby.edu\/mainebirds\/wp-json\/wp\/v2\/posts\/300\/revisions\/301"}],"wp:attachment":[{"href":"https:\/\/web.colby.edu\/mainebirds\/wp-json\/wp\/v2\/media?parent=300"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/web.colby.edu\/mainebirds\/wp-json\/wp\/v2\/categories?post=300"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/web.colby.edu\/mainebirds\/wp-json\/wp\/v2\/tags?post=300"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}