This EagleCam update
is brought to you by MN DNR’s Nongame Wildlife Program
Week of
March 20, 2017
It was a busy week, it was
a typical week, it was the best of all possible weeks in our favorite eagle
nest. The adults continued to hunt, bring food to the nest, and feed their
babies. The little ones continued to eat, sleep, and grow. The eaglets also exhibited
exploratory behavior that’s a sign of healthy development by stepping outside of the bole, or the cup-shaped
depression where the eggs were laid.
All three eaglets are now roughly
the same size, suggesting that all are getting fed and may successfully fledge
the nest (fingers crossed!). Alternatively, the presence of a “runt” could
indicate a physical impairment, such as a deformity or injury, or that the
larger siblings are eating all the food. Perennial viewers of our video stream
may recall such things happening in prior years.
This week, EagleCam
viewers may have seen a lot carnage in the nest. Indeed, many meals were
delivered, including fish and mammals, but this is typical and necessary for
sustained eaglet growth. Some viewers sent us messages about an especially
graphic scene in which a squirrel, still living, was brought to the nest. Different
viewers inevitably will have different opinions about predator-prey relationships
but, like it or not, this is an intrinsic part of nature. Carnivorous species,
like eagles, derive their energy and nutrient requirements from animal tissue. So
do many humans (although we prefer that our meat isn’t moving when we stick a
fork into it). The scene with the squirrel is a reminder to watch the EagleCam
with caution, especially when young children are present. Real nature can be
fascinating, but it isn’t a Disney flick.
Food For
Thought
For many, the best part of
traveling to other states and regions is tasting the local cuisine. For
example, the Carolinas specialize in barbeque and ribs, Louisiana uniquely
offers Creole and Cajun dishes, and here in Minnesota we love a good Juicy Lucy,
fish-fry Fridays and cheese curds. Similarly, bald eagles (and other widely
distributed species) specialize on foods that are locally abundant and
available where they live. Therefore eagles in different regions may have
different diets.
Because Minnesota has lots
of lakes and forests, Minnesotan eagles primarily eat fish and small to medium-sized
mammals (including cats, so keep your fur babies inside!). Alaskan eagles prefer
to scavenge salmon carcasses, and eagles living in the Prairie Pothole Region likely
specialize on waterfowl. One commonality among eagles, especially juveniles
that are not yet skilled hunters, is that they opportunistically eat carrion (decaying
animal tissue). Roadkill may sound gross to you, but to an eagle it’s a meal.
Prey type is directly
associated with method of prey capture, which includes hunting in flight, from
perches, and on the ground, as well as wading in water, cooperative hunting,
scavenging, and piracy. That last method, piracy, includes stealing prey from
other birds or mammals and displacing others from scavenging sites.
After catching and killing
prey, eagles go to work tearing off little pieces of tissue small enough to
swallow. This is a mighty task without the use of hands and teeth! Once
swallowed, the tissue first arrives in the crop, which basically is a storage
organ that allows birds to consume more food than would otherwise fit in their
stomach. From there, the tissue travels to the proventriculus,
or upper stomach, where it is broken down by digestive juices. Next, it
is further ground up, with the aid of grit, in the
ventriculus (gizzard) or lower stomach. Fats, sugars, and proteins are broken
down in the small intestine by bile and enzymes and absorbed into the blood
stream. As with all birds, eagles urinate and defecate simultaneously through
their cloaca, which also is used for copulation and egg laying.
Are you interested in birdwatching
but need a little help getting started? Fear not, Minnesota Parks and Trials is
hosting a Birdwatching for Beginners event this Saturday, March 25, at Brown’s Creek State Trail. Binoculars and field guides will be
available. Meet on Hazel Street in northern Stillwater by 8:00 AM, and contact
Linda Radimecky (651-231-6968, Linda.Radimecky@state.mn.us) for more
information.
Like what you read here? Want to learn more?
Your MN DNR Nongame Wildlife Program and the educational products it provides
(including the popular EagleCam), are made possible by donations from the
public. Please give today.
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