{"id":6789,"date":"2012-07-28T08:35:36","date_gmt":"2012-07-28T14:35:36","guid":{"rendered":"http:\/\/featheredphotography.com\/blog\/?p=6789"},"modified":"2012-09-01T19:20:06","modified_gmt":"2012-09-02T01:20:06","slug":"savannah-sparrow-parasitized-by-cowbirds","status":"publish","type":"post","link":"https:\/\/featheredphotography.com\/blog\/2012\/07\/28\/savannah-sparrow-parasitized-by-cowbirds\/","title":{"rendered":"Savannah Sparrow Parasitized By Cowbirds"},"content":{"rendered":"

Brown-headed Cowbirds are well-known for laying their eggs in the nests of other species – brood parasitism.\u00a0 A single cowbird female may lay up to 40 eggs in the nests of other species per season.\u00a0 More than 220 host species have been identified and at least 144 of those species have successfully raised the parasitic cowbird offspring.\u00a0 The physical size of the host species ranges from tiny 10 gram creepers to 150 gram meadowlarks.<\/p>\n

For a variety of reasons, the young of the parasitic cowbirds are more likely to survive than are those of the host species.\u00a0 The breeding success of the rare Kirtland’s Warbler has been severely reduced by cowbird brood parasitism.<\/p>\n

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\"savannah<\/p>\n

1\/1600 f\/7.1, ISO 400, 500 f\/4\u00a0<\/em><\/p>\n

\u00a0On our recent trip to sw Montana we found this Savannah Sparrow bringing food (insects, mostly\u00a0young grasshoppers)\u00a0to one of its fledglings on a fence\u00a0near our campground.<\/p>\n

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\"savannah<\/p>\n

\u00a01\/1600 f\/6.3, ISO 400, 500 f\/4 <\/em><\/p>\n

\u00a0But the fledgling was a cowbird and not a Savannah Sparrow.\u00a0 Cowbirds are more than twice the size of Savannah Sparrows by weight and that difference is obvious here.<\/p>\n

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\"savannah<\/p>\n

\u00a01\/1600 f\/7.1, ISO 400, 500 f\/4 <\/em><\/p>\n

The cowbird youngster was boisterous and rambunctious when food was brought in.\u00a0 I actually\u00a0had the impression that the adult sparrow was a little intimidated by the size and hyperactivity of the cowbird chick and the “parent” bird didn’t stick around for long\u00a0when food was delivered.<\/p>\n

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\"savannah1\/1600 f\/7.1, ISO 400, 500 f\/4 <\/em><\/p>\n

\u00a0After the chick swallowed this grasshopper the sparrow gave it another insect that is mostly\u00a0inside his\/her beak and can’t be seen well\u00a0in this photo.<\/p>\n

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\"savannah<\/p>\n

\u00a01\/1600 f\/7.1, ISO 400, 500 f\/4<\/em><\/p>\n

I thought this image showed best the dramatic size difference between the adult sparrow and the young cowbird.<\/p>\n

Lots of folks despise cowbirds for the negative effects their brood parasitism has had on songbird populations.\u00a0 But the dramatic increase in the range of the Brown-headed Cowbird in North America is largely due to the westward expansion of human settlements which reduced forests and increased agricultural and suburban landscapes, thus allowing for the spread of the cowbird.\u00a0 Personally I can’t blame the bird for that and as a biologist I marvel at the evolutionary selection process that produced this amazing behavior in the first place.<\/p>\n

Ron<\/p>\n","protected":false},"excerpt":{"rendered":"

Brown-headed Cowbirds are well-known for laying their eggs in the nests of other species – brood parasitism.\u00a0 A single cowbird female may lay up to 40 eggs in the nests of other species per season.\u00a0 More than 220 host species have been identified and at least 144 of those species have successfully raised the parasitic cowbird offspring.\u00a0 The physical size of the host species ranges from tiny 10 gram creepers to 150 gram meadowlarks. For a variety of reasons, the young of the parasitic cowbirds are more likely to survive than are those of the host species.\u00a0 The breeding success of the rare Kirtland’s Warbler has been severely reduced by cowbird brood parasitism.   1\/1600 f\/7.1, ISO 400, 500 f\/4\u00a0 \u00a0On our recent trip to sw Montana we found this Savannah Sparrow bringing food (insects, mostly\u00a0young grasshoppers)\u00a0to one of its fledglings on a fence\u00a0near our campground.     \u00a01\/1600 f\/6.3, ISO 400, 500 f\/4 \u00a0But the fledgling was a cowbird and not a Savannah Sparrow.\u00a0 Cowbirds are more than twice the size of Savannah Sparrows by weight and that difference is obvious here.     \u00a01\/1600 f\/7.1, ISO 400, 500 f\/4 The cowbird youngster was boisterous and rambunctious when food was brought in.\u00a0 I actually\u00a0had the impression that the adult sparrow was a little intimidated by the size and hyperactivity of the cowbird chick and the “parent” bird didn’t stick around for long\u00a0when food was delivered.     1\/1600 f\/7.1, ISO 400, 500 f\/4 \u00a0After the chick swallowed this grasshopper the sparrow gave it another…<\/p>\n

Continue reading<\/span><\/i><\/a> <\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_feature_clip_id":0,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":false,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2},"jetpack_post_was_ever_published":false},"categories":[334,442],"tags":[782,780,136,783,784,781,220,444,443],"class_list":["post-6789","post","type-post","status-publish","format-standard","hentry","category-birds","category-savannah-sparrows","tag-brood-parrasitism","tag-brown-headed-cowbird","tag-feeding","tag-host-species","tag-kirtlands-warbler","tag-mlothrus-ater","tag-montana-2","tag-passerculus-sandwichensis","tag-savannah-sparrow"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_shortlink":"https:\/\/wp.me\/p1zzJh-1Lv","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/featheredphotography.com\/blog\/wp-json\/wp\/v2\/posts\/6789","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/featheredphotography.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/featheredphotography.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/featheredphotography.com\/blog\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/featheredphotography.com\/blog\/wp-json\/wp\/v2\/comments?post=6789"}],"version-history":[{"count":0,"href":"https:\/\/featheredphotography.com\/blog\/wp-json\/wp\/v2\/posts\/6789\/revisions"}],"wp:attachment":[{"href":"https:\/\/featheredphotography.com\/blog\/wp-json\/wp\/v2\/media?parent=6789"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/featheredphotography.com\/blog\/wp-json\/wp\/v2\/categories?post=6789"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/featheredphotography.com\/blog\/wp-json\/wp\/v2\/tags?post=6789"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}