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<\/p>\nSince you’re reading this you’re probably a birder, bird photographer or nature lover and have seen your share of “pooping” birds. Well.., mostly it isn’t really poop in the traditional sense – its composition is a little different\u00a0than many folks think and that’s an adaptation that originated with the shelled egg.\u00a0\u00a0First a little background (and I promise not to use the word “poop” again…:<\/p>\n
Most mammals excrete their toxic nitrogenous wastes in the form of urea but\u00a0birds and reptiles produce uric acid instead.\u00a0There’s good reason for that. Urea is soluble in water and in mammals is excreted in their familiar urine. But birds\u00a0as developing embryos must survive their time\u00a0in the egg with their toxic wastes also enclosed within the shell (a problem not faced by mammals). If they produced\u00a0water-soluble urea it would quickly build to toxic levels within the egg and kill the embryo. So birds produce uric acid instead. Uric acid is insoluble in water and crystallizes out of solution and stored harmlessly within the\u00a0egg until hatching.<\/p>\n
“Thus from an embryonic necessity was born an adult\u00a0virtue”.\u00a0Adult birds concentrate and store uric acid within the cloaca before it is voided. Birds can excrete 1 gram of undissolved\u00a0uric acid in less than 3 ml of water but mammals require up to 60 ml of water to excrete the same amount of urea so this is also a weight-saving device for flight. Water (urine) is heavy – imagine trying to\u00a0 take off or maneuver in flight\u00a0with your\u00a0“tank” (urinary bladder,\u00a0a structure lacking in birds) full of sloshing urine…<\/p>\n
Sexual products (sperm and eggs), metabolic wastes (uric acid) and digestive wastes (feces) must all pass through the cloaca (which literally means “common sewer”), a storage chamber opening to the outside at the vent. So birds have only one opening to the outside for elimination of these products while mammals typically have two.<\/p>\n
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Ok, sorry for the heavy reading but\u00a0this explains some things we’ve all seen in the field. Birds excrete uric acid in the form of a relatively thick white paste (darker digestive wastes may also be included) instead of water based urine as in mammals.<\/p>\n
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![\"red-tailed](\"https:\/\/featheredphotography.com\/blog\/wp-content\/uploads\/2015\/05\/red-tailed-hawk-6298-ron-dudley.jpg\")
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That paste collects on habitual perches and\u00a0many of us call it “whitewash”. It can be aggravating to photographers\u00a0(and car owners) because some see it as unsightly (I’m well-known for not being a fan of bright perches in my photos) and because of its insolubility in water it’s incredibly persistent – I don’t think Noah’s floods would wash it away!<\/p>\n
This rocky perch, part of a huge boulder on the slopes of Antelope Island’s Frary\u00a0Peak, is a favorite perch for birds like Red-tailed Hawks, Chukars, Western Meadowlarks, Rock Wrens, Sage Thrashers and Lark Sparrows but I seldom use any photos of birds using the perch because the rock\u00a0is so heavily stained with whitewash. Several years ago I noticed that even after a huge rainstorm the whitewash had been unaffected so using some bottled water I attempted to scrub away a tiny portion of it as a test. It simply would not come off. Water has often been referred to as the “universal solvent” but obviously even water has its limits.<\/p>\n
Several of the following images are soft but I think they’re sharp enough to make my point.<\/em><\/p>\n <\/p>\n <\/p>\n Some birds take in so much water in their diet that excess amounts\u00a0of it must also be voided – many hummingbirds are a case in point. Flower nectar is mostly water so hummers have to\u00a0ingest a lot of it to\u00a0meet some of their nutritional requirements (something that those of us who put out feeders are well aware of). I photographed\u00a0this one as it was feeding on Rocky Mountain Bee\u00a0Plant on Antelope Island and just happened to squeeze the shutter as it voided some of that water. It also contains some white uric acid (out of solution of course) but as you can see it’s mostly water.<\/p>\n <\/p>\n <\/p>\n Prior to nesting season the Williamson’s Sapsucker’s diet is made up\u00a0almost\u00a0entirely of\u00a0tree sap harvested at sap wells like you see here (image taken on our last Montana camping trip a\u00a0few weeks ago).<\/p>\n <\/p>\n <\/p>\n Here you can see the male of the mated pair taking a sap break in-between bouts of defending (or attempting to establish) its nesting territory from the likes of\u00a0Northern Flickers, Mountain Bluebirds and Red-breasted Nuthatches. Tree sap is also mostly water so…<\/p>\n <\/p>\n <\/p>\n you guessed it, the bird soon voided a big batch it.\u00a0 After the eggs are laid these birds begin to consume lots of ants and at that point their wastes would also include dark\u00a0indigestible chitin from their exoskeletons.<\/p>\n I hope you’ll forgive or at least tolerate the bio-geekiness of this post. It won’t be for everyone but this stuff fascinates me so I just went with the flow… \ud83d\ude42<\/p>\n Ron<\/p>\n <\/p>\n <\/p>\n <\/p>\n <\/p>\n <\/p>\n","protected":false},"excerpt":{"rendered":" Since you’re reading this you’re probably a birder, bird photographer or nature lover and have seen your share of “pooping” birds.<\/p>\n![\"hummingbird](\"https:\/\/featheredphotography.com\/blog\/wp-content\/uploads\/2015\/05\/hummingbird-8285-ron-dudley.jpg\")
<\/p>\n![\"sapsucker](\"https:\/\/featheredphotography.com\/blog\/wp-content\/uploads\/2015\/05\/sapsucker-wells-7131-ron-dudley.jpg\")
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