Great Blue Herons
Great Blue Herons (Ardea herodias) are the largest
heron in North America standing fourto five feet tall,
with a wingspan of nearly sixfeet. In spite of its name,
it looks grey under most viewing conditions. When seen
in flight, if the light is right, the wing feathers will
take on a bluish cast. They eat mostly fish and small
mammals. They are found ...range... in marshes, rivers
and upland fields. Individual birds can be seen year-round
at the Elkhorn Slough wading in the shallow mud flats.
Great Blues can live to be 16 years old.
Each
season, the Great Blue Herons are the first to arrive
(usually late January - early February). When they arrive,
they perform elaborate mating
rituals to establish pair bonding. It is dificult
to distinguish males from females, as they both bear the
same plumage, including nuptial plumes.
Great Egrets
Great Egrets, like Great Blues are long-legged, long-necked
birds adapted for wading in shallow water such as lake
edges, marshes and tidal flats. Great Egrets are all white
with black legs and feet. They are distinguished by plumes
or "aigrettes" that grow from the shoulder and can be
elevated and spread fan-shaped during mating displays.
These
birds were nearly hunted to extinction at the turn of
the century when their plumage became a sign of high fashion.
In 1903 bird hunters received $32 an once for plumes and
each once required the deaths of four herons or egrets.
It is on record that at one single London auction in 1902,
3000 pounds of plumes were sold to haberdashers- that's
48,000 onces or 192,000 birds! It is one of the most important
stories of conservation. The British Royal Society for
Protection of Birds and the US Audubon Society were founded
by people who worked to stop this slaughter and now these
birds are protected and recoverering their numbers.
The
oldest Great Egret on record was 16 years old.
Raising
Young
Both
species build nests made of sticks, lined with green
needles. Females lay 2-5 light bluish -green eggs
at 2-3 day intervals. The adults take turns incubating
the eggs for 25-28 days. Chicks of both species
are sparsely covered with down on hatching. Heron
chicks are grey, egret chicks are white. The little
grey heron chicks hatch and are fed about 6 times
per day during the day and night. Egrets feed their
young fewer times. |
 |
Not all chicks survive to independence. In broods of 3 or
4, the chicks that hatch later are smaller and weaker than
their older nest mates. Older chicks aggressively peck the
younger ones at feeding time and force them away from the
food. If food is limited, the younger chicks die. Successful
adults raise 2 young, sometimes 3 and rarely 4.
Heron
young take their first long flight at about 8 weeks but
usually remain at the nest for up to 11 weeks.
Double-crested
Cormorants
Double-crested Cormorants are commonly seen along our
coastal cliffs and seastacks. Feeding mostly on schooling
marine fish, they are excellent swimmers and divers. The
Double Crested Cormorants have a complex courtship. Males
pursue females, splash forcefully with both wings, swim
rapidly in a zigzag until their heads are submerged then
dive and surface holding vegetation which the male then
drops near the female or tosses in the air. They nest
in the Rookery, sharing the same trees with the Herons
and Egrets. |
