FALL
(September - October - November)
Excellent opportunities to view herons in wetland habitats
throughout El Paso County occur during late summer and early fall days.
Parent birds, non-breeders and recently fledged young all gather
in these areas to feed, sunbathe, clean their feathers and roost.
Territorial disputes over prime provisioning sites occasionally disrupt
the calm. Though social ties no longer bind these birds, dominance patterns
persist.
From a distance, males cannot be distinguished from females. Except for
the slightly larger size of the male, the two appear similarly patterned
and colored. Non-breeding birds lack their elders' ornate head and neck
plumage, showing instead distinctly yellower bills. The heads of juvenile
birds, those in their first season, are black, not white like their parents.
As fruits ripen, leaves color and morning temperatures drop, the food production
cycles that sustain wetland residents begin to slow. Reptiles, amphibians
and insects seek shelter from frosts. Plants conclude their growing seasons,
and fish move into deeper water. Food for Great Blue Herons becomes less
accessible as ice forms on pond edges and the masking backdrop of cattails
and bulrushes brown and bend.
Adult herons leave first. Young birds follow within a week or
two.
A few herons winter along Fountain Creek. They probably migrate here from
rookeries far to the north. Herons have ample insulation to withstand the
cold if they can find enough food to maintain minimum body temperatures.
Despite some subzero days and periods when ice covers many area ponds, enough
open water and food resources remain to support these birds.
Migrations tax the strength, endurance and energy reserves
of long distance travelers.
Dangers and unexpected encounters often attend these journeys. Along the
way, hungry predators, unseen power lines and insufficient food supplies
end flights prematurely. Polluted resources, storms and adverse winds present
additional obstacles. Birds undernourished or sick at the beginning of this
flight seldom complete it. Juvenile birds are particularly vulnerable. Some
studies indicate a 70% mortality rate for this group during their first
year. Many of these losses occur on route to winter grounds. If a young
heron survives its first migration, chances improve for it to complete many
more.
Where do the Fountain Creek birds go?
The Great Blue Herons' winter range extends all the way to Columbia and
Venezuela. Some herons winter in Colorado, especially along the Platte and
Arkansas rivers. Large reservoirs neighboring these drainages also provide
valuable habitat. In central and southern New Mexico herons settle along
the Rio Grande River, but the largest concentration of birds from the plains
states gather on the Gulf of Mexico's coastal wetlands.
To know conclusively where the El Paso County herons winter would require
banding the nestlings, then recapturing them in January. The challenge of
coming face to face with an adult protecting its young or a solitary, beak-flailing
individual on its winter range complicates this type of census work.
