An online resource based on the award-winning nature guide – maryholland505@gmail.com

Archive for November, 2020

Northern Shrikes Arriving

The Northeast loses a lot of songbirds to migration in the fall, but it gains a few as well, one of which is the Northern Shrike (Lanius excubitor).   As days shorten and temperatures drop, this tundra-nesting bird migrates southward into southern parts of Canada and northern U.S., arriving in October and November on its wintering grounds. In some areas Northern Shrike movements and winter numbers have been associated with the movements of Snowy Owls and Rough-legged Hawks.

The Northern Shrike is highly unusual in that it is a predatory songbird. Birds, mammals and insects are preferred over nectar, nuts and seeds. During the winter it preys mainly on small mammals (voles, mice, shrews) and birds. The Northern Shrike often kills more prey than it can immediately eat or feed its young, storing the excess food to eat later when available living prey may be scarce. The manner in which it stores this extra food is what gave it the name “butcher bird;” it often impales prey on a thorn, broken branch or even barbed wire, or it wedges prey into narrow V-shaped forks of branches, where they hang until reclaimed by the shrike. (Photo by Mary Sue Henszey)

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Gypsy Egg Moths Prolific

The Gypsy Moth (Lymantria dispar dispar) was introduced to North America from France by E.L Trouvelot in 1869 who had hopes of breeding a silk-spinning caterpillar that was more resistant to disease than the domesticated silkworm.  Unfortunately, the caterpillars escaped into his backyard. About 10 years later, they began to appear in large swarms, and by the late 1880s they were causing severe defoliation in the area. Since then the Gypsy Moth has become one of the most destructive pests of hardwood trees in the eastern U.S. 

The adult female moths emerged from their pupae this summer.  With a life span of one week, the adults do not feed; they do, however, mate and lay eggs. Although the female moth has fully formed wings, she cannot fly.  She emits pheromones that attract males, mates and then lays a cluster of 75-1,000 eggs close to where she pupated.  She then covers them with buff-colored, hairlike setae from her abdomen, which serve as protection from predators and parasites.  The eggs overwinter and hatch in the spring.  The larvae have a voracious appetite and feed on more than 300 species of trees and shrubs. 

Gypsy Moth egg masses appear to be prolific this fall, perhaps because there has been no significant wet weather to fuel the fungus (Entomophaga maimaiga) that feeds on the Gypsy Moth. While there are other natural controls for Gypsy Moths (birds, squirrels, mice, etc.) they don’t prevent infestations.  If you wish to rid your woodlot of these caterpillars, you can remove the egg masses and pour boiling water over them.  Scraping the eggs onto the ground is less effective as they can survive temperatures of 20°- 30°F. degrees below zero.

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2021 Naturally Curious Calendar Orders

The Naturally Curious 2021 calendars have been mailed out, but due to a computer malfunction I am requesting that anyone who placed an order for one or more calendars and has not received them by the end of this week to please email me (maryholland505@gmail.com).  I want to be sure that every order is filled and no-one has been overlooked.  Thank you!

I also want to let you know that I ordered quite a few extra calendars this year, so if there’s anyone who didn’t make the ordering deadline and would still like to place an order, please feel free to do so. The calendars will be mailed out as soon as I receive your order.

Orders for the  2021 Naturally Curious calendar can be placed by writing to me at 505 Wake Robin Drive, Shelburne, VT  05482. The calendars are printed on heavy card stock and measure 11” x 17” when hanging. There is one full-page photograph per month. The calendars are $35.00 each (includes postage). Please specify the number of calendars you would like to order, the mailing address to which they should be sent and your email address (so I can easily and quickly contact you if I have any questions). Your check can be made out to Mary Holland. Thank you very much.


Bald Eagles Year-Round Residents In Much Of The Northeast

Most immature Bald Eagles migrate, but if adults have nested in an area where water remains open year-round, they are more likely to remain in or near their breeding territories all year, defending their nest site.  The risks that migrating pose are not worth it if they can get all the food they need (1/2 – 1 ½ pounds/day) to survive the winter, which they can in much of the Northeast.  In the past few decades, the number of overwintering eagles has been increasing in New England to the point where it is not unusual to see adult eagles near and even at their nests any month of the year. (The accompanying photo taken in Vermont on 11-14-20.)

Eagles do make changes in order to adapt to winter conditions.  While they continue to feed on fish, they also do a fair amount of scavenging in the winter, feeding on roadkills and animals such as deer that may have wandered onto the ice, fallen and not been able to get back up.

Another behavioral change that occurs is the tendency to gather in large numbers, clustering close together on branches at overnight roost sites.  Often stands of white pine provide the birds with some protection from the cold wind, thus allowing them to conserve energy.  An additional advantage of this communal life style is that they get cues from each other as to where sources of food may be by watching the direction in which the first birds take flight in the morning (those with a known source of food often are the first to leave the roost).

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Mergansers’ “Toothed” Bills

Hooded and Common Mergansers can be found year-round in most of the Northeast.  The bills of these cold-hardy, fish-eating ducks are distinctive in that they may be four times as long as wide.  In addition, their structure differs from the bills of other ducks in that most ducks have plates (lamellae) or ridges on the cutting edges of their bills that let water escape from the bill when they bring prey to the surface of the water.  In mergansers, these plates have been modified to look like saw blades – they aren’t true teeth (birds lack teeth), but are very toothlike – perfect for capturing slippery fish. (Photo: juvenile Common Mergansers)

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Black-and-Yellow Argiope Spiderlings Hatching

Some species of spiders (including wolf and jumping spiders) overwinter as young adults and mate/lay eggs in the spring. Many spiders, however, mate in the fall, after which they lay eggs and die. Their white or tan egg sacs are a familiar sight at this time of year. One might assume that these species overwinter as eggs inside their silken sacs, but this is rarely the case as spider eggs can’t survive being frozen. Spider eggs laid in the fall hatch shortly thereafter and the young spiders spend the winter inside their egg sac.

Although egg sacs provide a degree of shelter (the interior is packed with very fine, very soft silken threads), the newly-hatched spiderlings do have to undergo a process of “cold hardening” in the fall in order to survive the winter. On nights that go down into the 40’s and high 30’s, these young spiders start producing antifreeze compounds, which lower the temperature at which they freeze. By the time freezing temperatures occur, the spiders are equipped to survive the winter inside their egg sac – as spiderlings, not eggs.  (Photos:  Black-and-Yellow Argiope egg sac and spiderlings – egg sac had been pecked open by a bird)

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Beavers Gathering & Caching Winter Food Supply

Beavers are busy reinforcing their lodges and repairing dams as the days shorten and temperatures fall.  Once these tasks are taken care of, they begin gathering and storing all of the food that they will need this winter, for once ice forms they will no longer have access to land.

Their winter food cache is placed as close to the entrance of their lodge as possible, as the inhabitants of the lodge will be swimming out to this pile frequently to obtain food.  After hauling branches and saplings to the lodge, the beaver dives down and jabs the butt end of the branch into the mud at the bottom of the pond.  Additional branches are woven into this base layer until eventually most caches weigh two or more tons. One can often see the pile’s top branches and leaves rising above the surface of the water. 

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Northern Cardinal Nests: Safety in Numbers

This is the time of year to keep an eye out for bird nests that were hidden by leaves all summer. Their location can reveal more than one might guess.  As with many bird species, the female Northern Cardinal does most of the nest-building herself, usually selecting a site that is in dense shrubbery, often in a tangle of vines.  Frequently there are two broods, but rarely is a nest reused.  Instead, a new nest is built for the second clutch of eggs, and it can intentionally be located quite close to the first nest.

The two pictured Cardinal nests were both built this year, only four feet apart in a grape vine-covered stand of Staghorn Sumac. Two different birds would not have nested so close to each other due to territoriality; thus, the same bird most likely built both nests. Ornithologists feel that the presence of old nests may function as protection against predation.  They found that when they placed an empty Cardinal nest adjacent to a Cardinal nest containing plastic eggs, there was significantly less predation than with single Cardinal nests. (Thanks to Jody Crosby for photo opportunity.)

(NB:  Even though most songbirds only use their nest once and then abandon it,  one needs a federal permit to collect bird nests.)

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