{"id":1535,"date":"2011-03-20T11:04:33","date_gmt":"2011-03-20T17:04:33","guid":{"rendered":"http:\/\/featheredphotography.wordpress.com\/?p=1535"},"modified":"2011-05-30T07:26:33","modified_gmt":"2011-05-30T13:26:33","slug":"fish-eating-northern-harriers","status":"publish","type":"post","link":"https:\/\/featheredphotography.com\/blog\/2011\/03\/20\/fish-eating-northern-harriers\/","title":{"rendered":"Fish Eating Northern Harriers"},"content":{"rendered":"

\u00a0As I’ve mentioned before in this blog, the winter of 2008 was a particularly brutal one in northern Utah.\u00a0 During January and February there was much more snow than usual and it was bitterly cold.\u00a0 During most winters our Northern Harriers rely primarily on voles as a food supply but in 2008 with the voles under the deep crusty snow\u00a0our harriers were desperate for food.\u00a0<\/p>\n

Birds of North America Online provides extensive information on the dietary habits\u00a0of harriers.\u00a0 It lists small to medium-sized mammals (primarily rodents), birds, reptiles and frogs as harrier food sources, stating further that the diet of harriers during winter in their northern range (which includes northern Utah) consists of voles “almost exclusively”.\u00a0 I can find no mention of harriers eating fish, ever!<\/em><\/p>\n

Each year in early February some of our wetlands managers treat some of our ponds with rotenone (a chemical that prevents oxygen from being absorbed across fish gill membranes)\u00a0in an effort to control the invasive and damaging carp that do so much damage to the emergent vegetation which is so vital for waterfowl.\u00a0\u00a0So, in 2008 for a few weeks, our desperate and\u00a0starving harriers began to eat\u00a0fish!\u00a0 In the three winters since then I have never seen harriers eating fish even though the dead carp are always plentiful after the rotenone kill.\u00a0<\/p>\n

\u00a0<\/p>\n

\"Northern<\/p>\n

1\/1250, 1\/1000, ISO 500<\/em><\/p>\n

Many of the carp are brought to\u00a0the shores or ice surface by Bald Eagles which\u00a0makes them available to the harriers who generally cannot retrieve them from the water.\u00a0<\/p>\n

\u00a0<\/p>\n

\u00a0<\/p>\n

\"Northern<\/p>\n

1\/1250, f\/8, ISO 500<\/em><\/p>\n

An immature male harrier landing on a small carp.\u00a0<\/p>\n

\u00a0<\/p>\n

\u00a0<\/p>\n

\"Immature<\/p>\n

1\/1000, f\/8, ISO 500<\/em><\/p>\n

As you can see in the background, at times the eagles provided a bounty of fish for the harriers to eat.<\/p>\n

\u00a0<\/p>\n

\u00a0<\/p>\n

\"Harriers<\/p>\n

1\/800, f\/8, ISO 500<\/em><\/p>\n

Harriers\u00a0would often compete for\u00a0and even fight over the fish.\u00a0 These are typical threat\/possession\u00a0postures when more than one bird was on the carp.\u00a0<\/p>\n

\u00a0<\/p>\n

\u00a0<\/p>\n

\"Displaying<\/p>\n

1\/1000, f\/8, ISO 500<\/em><\/p>\n

This immature male was sated and apparently not hungry but he still couldn’t resist claiming possession of the fish by continually resting his foot on the\u00a0carp as\u00a0he watched warily for other birds to come in and challenge him for the prize.<\/p>\n

\u00a0<\/p>\n

\u00a0<\/p>\n

\"Preparing<\/p>\n

1\/1000, f\/8, ISO 500<\/em><\/p>\n

But males are roughly one third smaller than adult females (sexual dimorphism)\u00a0and whenever a male would see an adult female coming in to challenge him for the food he would beat a hasty retreat, as this one is preparing to do.<\/p>\n

\u00a0<\/p>\n

\u00a0<\/p>\n

\"Another<\/p>\n

1\/1000, f\/8, ISO 500<\/em><\/p>\n

Here’s another posture that apparently displays “possession” to other birds in the area.\u00a0 At times they would even spread their wings over the\u00a0 fish as they were eating.\u00a0\u00a0<\/p>\n

\u00a0<\/p>\n

\u00a0<\/p>\n

\"Aggression<\/p>\n

1\/1000, f\/8, ISO 500<\/em><\/p>\n

However, “possession displays”\u00a0often didn’t work and fights\u00a0were commonplace.<\/p>\n

\u00a0<\/p>\n

\u00a0<\/p>\n

\"Not<\/p>\n

1\/640, f\/10, ISO 400<\/em><\/p>\n

Less dominant birds were often left to feed over scraps.\u00a0<\/p>\n

\u00a0<\/p>\n

\u00a0<\/p>\n

\"Not<\/p>\n

1\/1000, f\/10, ISO 400<\/em><\/p>\n

And at times those scraps were minimal indeed!<\/p>\n

\u00a0<\/p>\n

\u00a0<\/p>\n

\"A<\/p>\n

1\/1250, f\/10, ISO 400<\/em><\/p>\n

A few carp were quite large but even the big ones were quickly picked clean by the ravenous harriers.<\/p>\n

\u00a0<\/p>\n

\u00a0<\/p>\n

\"Sharing<\/p>\n

1\/1250, f\/8, ISO 400<\/em><\/p>\n

At times more than one bird would feed on a fish simultaneously but it wasn’t a comfortable arrangement and their stress from doing so was obvious.\u00a0 But when another bird would come in to challenge them…<\/p>\n

\u00a0<\/p>\n

\u00a0<\/p>\n

\"Incoming\"<\/p>\n

1\/800, f\/10, ISO 400<\/em><\/p>\n

it could be pretty dramatic!\u00a0<\/p>\n

\u00a0<\/p>\n

\u00a0<\/p>\n

\"Landing<\/p>\n

1\/2000, f\/8 Iso 400<\/em><\/p>\n

Landing on the carp’s head.\u00a0 This harrier had a particular fondness for perching on the head of the carp even when it wasn’t feeding.<\/p>\n

\u00a0<\/p>\n

\u00a0<\/p>\n

\"Landing<\/p>\n

1\/1250, f\/10, ISo 400<\/em><\/p>\n

As an indication of just how difficult this particular winter was for a variety of birds this Song Sparrow spent quite a while feeding on what’s left of this fish – something I have never seen before.\u00a0 If you look carefully you can see a morsel of fish flesh in the tip of the bill.\u00a0 The winter of 2008 was very good for bird photography but extremely difficult for many of\u00a0our birds.\u00a0 For their sake I hope such conditions don’t happen again soon.<\/p>\n

Ron<\/p>\n

PS –\u00a0a word of explanation about my camera settings (techs) for these images.\u00a0 Many of them were poorly chosen, even illogical.\u00a0 My excuse is that at the time I was still a digital\u00a0photography beginner and had very little experience with my new 500 mm lens.\u00a0 My chosen settings for most of these shots would be quite different now.\u00a0 All images in this post were taken with a Canon XTi, Canon EF500mm\u00a0f4L IS USM lens, mostly with attached 1.4 tc, from a tripod (some from within a blind).<\/p>\n","protected":false},"excerpt":{"rendered":"

\u00a0As I’ve mentioned before in this blog, the winter of 2008 was a particularly brutal one in northern Utah.\u00a0 During January and February there was much more snow than usual and it was bitterly cold.\u00a0 During most winters our Northern Harriers rely primarily on voles as a food supply but in 2008 with the voles under the deep crusty snow\u00a0our harriers were desperate for food.\u00a0 Birds of North America Online provides extensive information on the dietary habits\u00a0of harriers.\u00a0 It lists small to medium-sized mammals (primarily rodents), birds, reptiles and frogs as harrier food sources, stating further that the diet of harriers during winter in their northern range (which includes northern Utah) consists of voles “almost exclusively”.\u00a0 I can find no mention of harriers eating fish, ever! Each year in early February some of our wetlands managers treat some of our ponds with rotenone (a chemical that prevents oxygen from being absorbed across fish gill membranes)\u00a0in an effort to control the invasive and damaging carp that do so much damage to the emergent vegetation which is so vital for waterfowl.\u00a0\u00a0So, in 2008 for a few weeks, our desperate and\u00a0starving harriers began to eat\u00a0fish!\u00a0 In the three winters since then I have never seen harriers eating fish even though the dead carp are always plentiful after the rotenone kill.\u00a0 \u00a0 1\/1250, 1\/1000, ISO 500 Many of the carp are brought to\u00a0the shores or ice surface by Bald Eagles which\u00a0makes them available to the harriers who generally cannot retrieve them from the water.\u00a0 \u00a0 \u00a0 1\/1250, f\/8, ISO…<\/p>\n

Continue reading<\/span><\/i><\/a> <\/p>\n","protected":false},"author":1,"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":[8,392,394,341],"tags":[43,69,74,86,107,141,171,234,268,276,290,304,311,315],"class_list":["post-1535","post","type-post","status-publish","format-standard","hentry","category-ecology-and-environment","category-feeding-bird-behaviors","category-fighting-bird-behaviors","category-northern-harriers","tag-bald-eagle","tag-canon-ef500mm-f4l-is-usm-lens","tag-carp","tag-circus-cyaneus","tag-diet","tag-fish","tag-harrier","tag-northern-harrier","tag-rotenone","tag-sexual-dimorphism","tag-song-sparrow","tag-threat-posture","tag-utah-2","tag-vole"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_shortlink":"https:\/\/wp.me\/p1zzJh-oL","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/featheredphotography.com\/blog\/wp-json\/wp\/v2\/posts\/1535","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\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/featheredphotography.com\/blog\/wp-json\/wp\/v2\/comments?post=1535"}],"version-history":[{"count":0,"href":"https:\/\/featheredphotography.com\/blog\/wp-json\/wp\/v2\/posts\/1535\/revisions"}],"wp:attachment":[{"href":"https:\/\/featheredphotography.com\/blog\/wp-json\/wp\/v2\/media?parent=1535"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/featheredphotography.com\/blog\/wp-json\/wp\/v2\/categories?post=1535"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/featheredphotography.com\/blog\/wp-json\/wp\/v2\/tags?post=1535"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}