SUMMER
(June - July - August)
By June, heron parents turn their attention
to food gathering and feeding the new family.
To fill the ever-hungry mouths, individual birds may travel 20 miles from
the rookery in search of meals. Herons look for fish, amphibians and other
delicacies in shallow ponds or along wetland edges. When one returns, its
mate squawks and beak clacks a welcome greeting before departing on its
own quest for a meal and more for the nestlings. Herons carry food in a
pouch-like widening of the throat known as a crop. Limited digestion of
the crop's contents begins during transport back to the nest.
Heron cuisine includes: fish, aquatic insects, grasshoppers,
dragonflies,
crayfish, crustaceans, mice, shrews, pocket gophers,
ground squirrels, small muskrats, toads, frogs, lizards and snakes.
Undigestible parts are regurgitated in pellets.
Adults regurgitate these partially prepared meals directly into the beaks
of begging hatchlings. As the young gain size and mobility, this pattern
changes. Soon parents leave regurgitated food on the floor of the nest,
causing competition to attend meal times. Eventually they return with unaltered
food. If provisions dwindle, the dominant, aggressive traits of the first-born
become evident. Unless parasites or disease have weakened it, this sibling
will get its fill and grow faster than the others, favoring its chances
for survival. During periods of food scarcity, half of the season's nestlings
may perish in their first month.
Threats other than starvation accompany the flightless days
of June and early July.
Hungry eagles, hawks, and owls occasionally prey upon rookery young. The
presence of protective parents among neighboring nests limits this danger.
Gusty winds extract a higher toll.
Though coarsely constructed from our perspective and perched precariously
in treetops, heron nests normally withstand the elements. Supporting limbs,
however, may snap under the added stresses of storms. Squalls claim more
young than nests. Most bird species feed and attend to dislodged nestlings.
Heron parents will not. Though superbly adapted to canopy, shallow water
and shoreline habitats, herons lack maneuverability on the forest floor.
Their long wings and slow, pumping talk-off flap make an agile escape from
predators impossible. As a result, heron parents do not care for downed
offspring. Unable to feed themselves or fly, these hapless youngsters soon
perish.
By mid-July, the young, now almost full-grown, crowd the nest
and adjacent limbs, waiting for less frequent visits by parents with food.
This intentional weaning spurs the nestlings' budding instincts to fly and
find food for themselves. Wing flapping and short glide flights to neighboring
branches now typify the visible activity in the rookery. By the third week
in July, the number of perched silhouettes in the nesting trees declines
drastically.
Newly fledged young follow their parents to nearby feeding areas where they
watch them spear for food. Along wetland edges novice foragers mimic their
elders' hunting behaviors and hone their own survival instincts. Herons
employ two basic hunting tactics. Long legs enable them to wade offshore
where they either stand still and wait for passing prey or furtively stalk
and scan for movement ahead. Their slate blue colors, streaked with white,
brown and black, blend into marsh reflections and disguise their intent.
After four or five days of practice, immature herons become adequately skilled
at feeding themselves. Their hunting successes improve with age and experience.
Family ties loosen as the young gain independence. Many adults leave their
young and usual haunts at this juncture for distant, less crowded wetlands.
Juveniles prefer to stay in familiar surroundings.
By August, quiet returns to the rookery.
Occasionally birds will perch among the nests, but most spend their nights
in trees close to their feeding grounds. Without young to tend or show the
ways of spear fishing, bonds between paired adults weaken, and the solitary
instincts of the previous winter return.
