The alula or “bastard wing”\u00a0(plural – alulae) is the freely moving “thumb” or first digit of a bird’s wing.\u00a0 It bears 3, 4 or 5 small flight feathers, depending on species.\u00a0 The alula is like a small “winglet” attached to the wing.\u00a0 Normally the alula is held flush against the wing where it is seldom noticed but at slow flight speeds or when landing or taking off it\u00a0can extend forward.\u00a0 This creates a small slot\u00a0on the\u00a0leading edge of the wing which functions\u00a0similarly to the slats on the wing of an aircraft (which are also extended at slow speeds) and results in increased lift which prevents a stall at slow flight speeds.<\/em><\/li>\n<\/ul>\n <\/p>\n
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Two frames in the burst later the alula has extended again (I believe it retracts on the up-beat but someone please correct me if I’m wrong).<\/p>\n
One of the field marks of the Rough-legged Hawk is the conspicuous, almost square, dark carpal patch at the bend of the wing.\u00a0 I was struck by how well the dark colors and even patterns of that patch are continued into the extended alula.\u00a0 To this day researchers apparently aren’t sure if birds have muscular control over the alulae or\u00a0their positions are determined by air pressure on the wing but evidence seems to be leaning to the latter.<\/p>\n
Perhaps all this is of interest only to those of us who are “bird geeks” but when I notice something like this I can’t resist sharing…<\/p>\n
Ron<\/p>\n
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Yesterday morning a Rough-legged Hawk gave me a perspective on the alula that I had never seen (or at least noticed) previously. I was on the verge of deleting these images when at the last second something about the left wing caught my eye.<\/p>\n
Continue reading<\/span><\/i><\/a> <\/p>\n","protected":false},"author":2,"featured_media":20741,"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":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2},"jetpack_post_was_ever_published":false},"categories":[5,334,395,358],"tags":[953,1348,1349,534,1761,679,269],"class_list":["post-20740","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-bird-oddities","category-birds","category-miscellaneous","category-rough-legged-hawks","tag-alula","tag-alulae","tag-bastard-wing","tag-buteo-lagopus","tag-carpal-patch","tag-field-marks","tag-rough-legged-hawk"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"https:\/\/featheredphotography.com\/blog\/wp-content\/uploads\/2013\/12\/rough-legged-hawk-8071-ron-dudley.jpg","jetpack_shortlink":"https:\/\/wp.me\/p1zzJh-5ow","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/featheredphotography.com\/blog\/wp-json\/wp\/v2\/posts\/20740","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=20740"}],"version-history":[{"count":0,"href":"https:\/\/featheredphotography.com\/blog\/wp-json\/wp\/v2\/posts\/20740\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/featheredphotography.com\/blog\/wp-json\/wp\/v2\/media\/20741"}],"wp:attachment":[{"href":"https:\/\/featheredphotography.com\/blog\/wp-json\/wp\/v2\/media?parent=20740"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/featheredphotography.com\/blog\/wp-json\/wp\/v2\/categories?post=20740"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/featheredphotography.com\/blog\/wp-json\/wp\/v2\/tags?post=20740"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
![\"rough-legged](\"https:\/\/featheredphotography.com\/blog\/wp-content\/uploads\/2013\/12\/rough-legged-hawk-8071-ron-dudley.jpg\")
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