On Friday we did the Bird Survey on the 7 islands in the Pinellas NWR with Barb and Dave Howard, co-founders of the Friends of the Tampa Bay NWR's
Lindsay
Our largest heron (Great Blue Heron) checking us out
After a successful dive (Brown Pelicans are the only one of the pelican species worldwide that dive for their food), this young Brown Pelican
prepares to swallow the fish it caught
Osprey
Not many places on its body that a pelican can't reach when preening this all-important feathers
Brown Pelican juvenile getting his adult plumage as its head feathers change from brown to white
Juvenile Brown Pelican
A pair of Cattle Egrets flew over
Osprey on the hunt
Little Blue Heron in transitional plumage between its all-white juvenile plumage and its all-blue adult plumage
Adult Little Blue Heron on the left and a Juvenile on the right
The old "Pre-flight Dump"
Humans and other mammals metabolize nitrogen to urea, which is less toxic than ammonia andean restored in dilute form in a urinary bladder until it is convenient to pass. However, a bladder that stores urine increases body weight and also increases the need to drink to compensate for water loss with the urine.
Neither of these conditions is in the best interest of birds, which have adapted weight-loss adaptations for flight and methods for water conservation.
To avoid the toxicity of ammonia and the extra weight of a urinary bladder, birds, in their kidneys, metabolize nitrogen waste to uric acid, a white, chalky precipitate that is not only non-toxic but almost dry and to decrease weight they will often excrete this precipitate before flying.
Note the straight, spear-like bill on the Anhinga and the hooked bill tip on the Double-crested Cormorant.
Take off
Osprey in complete control with flaps down for a landing
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