Blog #348 The Scoop on Osprey Poop

A fledgling jettisoning feces over the side of the nest, courtesy of Andy Morffew. 

What’s the scoop on that fishy white excrement Ospreys jettison while in flight or over  the sides of their nests? We do it, they do it, all animals do it. Every animal excretes  waste products from its body (except for demodex mites, which don't have anuses and  simply store waste in their bodies until they die.) 

Ospreys, like humans, defecate undigested remains from the food they’ve consumed.  Also like humans, Ospreys produce nitrogenous waste as a byproduct of digesting their  food into molecules usable by the body’s cells. Humans excrete excess nitrogen as  urea diluted in water or urine. Birds are more conservative. 

Staying light for flight, Ospreys and other birds do not have heavy bladders like ours. They also need their metabolic water reserves for other things, such as long distance  flights. Ospreys and other birds excrete nitrogen in the undiluted, white pasty form of  

uric acid. (Osprey fetuses excrete uric acid inside eggs and neatly stored until hatching.) The darker parts of the feces include undigested food and waste products and are 

Feces are ejected from the single vent or cloaca. 

simultaneously evacuated with the uric acid from the cloaca (vent under the tail). The  cloacal sphincter muscle provides ejaculatory force, as demonstrated in the photo above. 

Osprey guano has high levels of nutrients like nitrate and ammonium salts and chemical  elements such as phosphorus, calcium, and magnesium. By mass, bird guano is 8–21%  nitrogen; the nitrogen content is about 80% uric acid, 10% protein, 7% ammonia, and  0.5% nitrate. Ospreys improve the habitat around their nests by spreading their  nutritious waste to the nutrient deficient soils along the shoreline. Their rich, fishy, oily  excrement fertilizes and helps build the soil around the Osprey nests. 

Raptors like ospreys and owls eat whole organisms and digest almost everything. Owls  are well-known for regurgitating pellets of hair, bones, claws, and undigested parts of  the small animals they eat after a meal. Ospreys make compact pellets of scales, fins,  and other indigestible bits. Leaving pellets results in little solid waste in their droppings.  The areas around their nests and eating perches get covered with "whitewash"  droppings and the occasional pellets.

Ospreys occasionally bring up pellets consisting of indigestible material such as fish bones and scales, courtesy of Leicestershire and Rutland Wildlife Trust. 

. 

From birth, Osprey hatchlings instinctually defecate over the rim of the nest and seldom  make messes in the nest—but accidents happen. Earlier today, Lilibit missed her target  and covered Rosie’s head in white. Usually it’s Ophelia who is the recipient of such an  unwelcomed gift from a young hatchling, but she is able to take a quick bath. Rosie,  while fledged, is not quite ready to do that. 

Eyes to the sky! 

Candace  

Candace E. Cornell  

Friends of Salt Point  

Cayuga Osprey Network 

Lansing, NY  

cec222@gmail.com 

EYES ON OSPREYS 

WATCH!

Salt Point Osprey Nest Cam 2021 

READ! 

On Osprey Time—A Blog on the Ospreys of Salt Point 

VISIT! 

Cayuga Lake Osprey Trail 

HELP PROTECT OSPREYS 

• AVOID GETTING TOO CLOSE TO NESTING SITES DURING THE BREEDING SEASON. IF THE BIRD  VOCALIZES, YOU ARE TOO CLOSE! BACK OFF IMMEDIATELY. 

• CARRY BINOCULARS TO VIEW WILDLIFE FROM AFAR. 

• RESTORE, CLEAN, AND PRESERVE LAKESHORE AND WETLAND HABITAT. • RECYCLE USED FISHING LINE, WHICH CAN BE HAZARDOUS TO OSPREY.  

• JOIN THE CAYUGA OSPREY NETWORK AND VOLUNTEER TO HELP MONITOR OSPREY NESTS. WRITE TO: CEC222@GMAIL.COM.

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