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Posts Tagged ‘biology’

USFWS Feather Atlas

September 2nd, 2011

USFWS Feather Atlas

Click here -> USFWS Feather Atlas.  This is a great resource for feather research and matching feathers to birds.

Raptor Biology , , ,

Raptor Mating Season

March 2nd, 2011

Raptor Mating Season

Raptors begin their nesting cycle in late winter / early spring.  I’ve noticed recently that the hawks are already paired up along my drive-route to work.  The other day, I observed three separate pairs of Red-Tailed hawks perching in prominent trees.  These perches appeared to be located near prime hunting grounds and in one case, in the same tree as a large nest.

Hawk nests are found in large, tall trees from 34 to 86 feet high in the forks of large branches and limbs. The structure of the nest is large, flat, and shallow, made of sticks and twigs about 1/2 inch in diameter. Male and female Red-Tails work together on nest construction. Nest sites may be used from year to year, since there is strong evidence that hawks mate for life. If the old nest is damaged by the wind or other weather events, new layers of new nesting material are added. Nests that are reused from year to year can grow to be very large with several layers of materials.

Red-Tailed Hawks are not the only raptors starting to pair up.   A few weeks ago, my wife heard some noises outside the house at night. Deep, resonating hoots could be heard from the backyard as a pair of Great Horned Owls were roosting in the large pine tree back in the swamp.  After listening to them for a bit, we noticed them flying over the house and into the front yard.  Watching them out the front window, in the dark, it was easy to see the big silhouettes high up in the cottonwood tree.  Owls begin their mating cycle earlier in the winter, sooner than Hawks, as the young take longer to fledge the nest.

 

Happy Nesting and Raptor Watching!

Raptor Biology , , ,

Red-Tail Nest

June 8th, 2009

Nesting Red-Tail Hawks

 

 

Finding the nesting site for a pair of Red-Tail Hawks can be difficult, considering that red-tails are very common and can be found almost anywhere in the lower 48 states. Once you do find a nest, it is quite the treat to be able to watch the parent hawks come and go from the nest in order to care for their young one.

The courtship habits of Red-Tailed hawks use arial displays that demonstrate their ability level and eagerness for breeding.  The close of winter usually signifies the start of the breeding season for the Red-Tailed hawk.  Red-Tails are monogamous and they choose their mate for life. They will however, choose aonther mate if the original partner dies.

 

Both the male and the female help build the nest together, at a mutually agreed site.  The nesting site is anywhere from 20 to 80 feet from the ground.  Nests are built on cliffs occaisionally. Red-Tailed haws are indeterminate egg layers, where the female hawk will lay from 1 to 5 eggs in the nest, but 2 eggs is a standard brood size. The eggs are a pale blue with some dark splotches (small spots) on the eggs. Red-Tail hawk eggs have an incubation period of 28-35 days. After about 45 days after hatching, the young brancher will leave the nest in search of food on his own.  

 

There are additional pics in the Picture Albums here.

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