Thursday, April 11, 2013

Great Blue Heron Rookery at Refuge

Great Blue at Hagerman NWR by Carol Ann Sowell

The Great Blue, a favorite sight year around at HagermanNational Wildlife Refuge, makes its nest in a group of the tallest trees on the horizon, looking south from the Harris Creek Bridge.  
Heron Rookery

The Herons, members of the Ardeid family, are seasonally monogamous, according to (Sibley, 2001) The Sibley Guide to Bird Life & Behavior, and breed in colonies.

The male and female cooperate in building the nest, which is usually located near water.  In colonies with mixed species, they tend to nest in tall trees, and may reuse the nests from one year to the next, adding on or refurbishing.

Herons have a single one brood each year, with from 2 – 7 eggs.  Parents take turns incubating which usually begins as soon as the first egg or two are laid.  When the chicks hatch they may be different sizes due to varied time under incubation.
The chicks, who make continuous food-begging calls, (Sibley, 2001)are fed by the parents, who regurgitate it into their mouth or onto the nest.  By two weeks in age moat chicks are ready to leave the nest and perch nearby.

If you visit the Refuge soon, be sure to look for the rookery as you cross Harris Creek Bridge.

NOTE:  David Sibley will be at Hagerman NWR for BirdFest Texoma.  He will present a painting demonstration at Evening with David Allen Sibley, and the painting, A Painted Bunting, will be up for auction at the close of the evening; register for this event at (no tickets will be sold at the door).  Sibley will also sign books from 11 am - Noon at the Refuge, May 4, and following the evening presentation.

Photos of  Rookery by Dick Malnory

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