Feed me, feed me!
Update from the nest
Our
three eaglets are now focused on the business of growing up, eating plenty and
getting strong. They’re a full-time job for the adult eagles, in need of frequent
feedings and help staying warm, but these adults have proved their mettle as
parents. Fish, pigeons, muskrat and squirrel have all made appearances at meal
times, and both adults are taking turns keeping the chicks protected from the
March winds of Minnesota.
Sibling squabbles
Competition
starts early in the life of a bald eagle. As we’ve seen, bald eagle chicks
hatch asynchronously, meaning they
don’t all hatch at the same time. A few days difference in age means
differences in size and strength for the first weeks of their lives outside the
shell, resulting in sibling rivalry. At this young age, one eaglet is unlikely
to really hurt another, but that doesn’t keep them from trying! Viewers may see
tiny grey heads bashing each other during feeding times. This behavior is a
normal and healthy part of early life for an eaglet. Working to get to the best
food bits first, to have the most comfy spot in the nest and the most parental
attention helps eaglets grow strong and smart. Eagles’ lives don’t get easier
once they fledge and join the adult population, so it’s very important they
develop a competitive spirit early on.
Parental strategies
Parenting
human children, someone once said, is like making chili; everyone has their own
recipe. That’s true in the animal kingdom, too, where biologists describe two
basic approaches to caring for the young. Some species are referred to as precocial – their young are mobile and
pretty much able to take care of themselves as soon as they’re born or hatched
(what parents of any teenager might occasionally find themselves longing for).
Horses, giraffes, domestic chickens, ducks and turkeys – all are precocial. The
super-precocial African wildebeest has calves that can stand within six minutes
of birth, and outrun their main predator, the hyena, within a day, giving them
a significant survival advantage.
Other
species are altricial – they need
lots of care and feeding for at least a while after being born or hatched. Most
backyard songbirds are altricial, as are eagles and other raptors. That’s why
we get to be intimate witnesses to all that goes on in our bald eagles’ nest. If
eagles were precocial, they’d fly off shortly after being hatched, and there
wouldn’t be much to see.
Altricial
development may offer benefits to the species, as well as to us spectators. Altricial
birds, like eagles, hatch with fairly small brains, but the rich parent-provided
diet after hatching lets their brains grow larger and more complex than
precocial birds, providing advantages for survival. It certainly seems to work
that way for humans. Altricial development also tends to promote greater
socialization, as parents may need to work together to provide care for their
young. Certainly we see that with our bald eagle pair!
While
humans may be at one end of the altricial development scale, taking as much as
18 years for the young to become mature (sometimes more – much more!), such
traits are not confined to higher order critters. Some insects such as ants and
bees also can be categorized as altricial. One fascinating group of beetles,
known as burying beetles, displays a surprising amount of parental care. True
to their name, burying beetles chew up and bury the bodies of small animals as
food for their larvae. Both parents then guard the larvae and the carcass/food
from other intrusions, and they will feed the squiggling larvae a regurgitated
liquid protein in response to begging. It is particularly noteworthy that male
burying beetles participate in parental care alongside the females. Although
the burying beetle larvae are capable of moving about and feeding on their own,
the parental care shown by burying beetles is thought to produce fewer but
larger and stronger adults.
Service interruption
The EagleCam will be temporarily offline from about 5 p.m. on
Friday, March 17, until about noon on Saturday, March 18, while the DNR makes
upgrades to our web service. We apologize for any inconvenience, but with
temperatures projected to warm into the mid-40s Friday and Saturday, it could
be a great time to get outdoors and look for eagles and other birds beginning
to return to Minnesota. Like those birds, we’ll be back.
The MN-DNR EagleCam is brought to
you by the Nongame
Wildlife Program, which is
supported almost entirely by voluntary donations. Please consider designating a
gift on Line 21 of your Minnesota income tax form, or donate online here.
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