An online resource based on the award-winning nature guide

August

Caddisfly Eggs Hatching

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The Mystery Photo was of a caddisfly’s egg mass which had been deposited on the leaf of a Turtlehead plant that was growing adjacent to the water, so that when the eggs hatch, the larvae will drop straight down into the water. (Congratulations to “bcottam2014,” the first person to correctly identify the Mystery Photo!)

Almost all caddisflies lay their eggs in the water, but in New England there is a family of northern case makers (Limnephilidae) whose members deposit an egg mass above the water on vegetation (see photo). After hatching and dropping into the water, these caddisflies will spend anywhere from two or three months to two years as aquatic larvae and pupae, emerging as adults with about a thirty day lifespan.

While they are larvae, most northern case-making caddisflies have silk glands with which they construct portable cases or attached retreats. Each species of caddisfly builds the same type of case, out of similar material, thus, it is possible to identify the species of caddisfly you’ve encountered from the appearance of its case.  Some species use pebbles, some bits of leaves, some sticks. Vegetative material must be chewed into just the right size and shape pieces. The caddisflies use these cases as a source of camouflage, physical protection and as a means of acquiring food.  When it comes time to pupate, they build cocoons within their cases.

Emergence of adults eventually takes place and for the next month or so they live a terrestrial life.  Like their close relatives, butterflies and moths, adult caddisflies have wings, but they are easily distinguishable from moths and butterflies due to the  tent-like slant the caddisfly holds its wings in when not flying. (Photo:  caddisfly larvae hatching from egg mass; inset – older caddisfly larva inside pebble case it built)

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Mystery Photo

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Do you recognize the spotted jelly-like blob on the lower right leaf of this Turtlehead (Chelone glabra) plant?  If so (or even if you want to make a wild guess), go to the Naturally Curious blog (www.naturallycuriouswithmaryholland.wordpress.com), scroll down and click on “Comments” to submit your entry. Look for the answer in the next Naturally Curious post.  (Hint:  Turtlehead likes its feet damp.)

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Moose & Climate Change

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If predictions for the future of our climate are accurate, and if no significant measures are taken to counter it, one of the hardest hit animals in North America will be the Moose.  While well-adapted to winter conditions, Moose start experiencing heat stress when summer temperatures get above 57°F. Why this intolerance to heat?  A highly insulative coat, thick skin and low surface to volume ratio.  When faced with very warm summers, Moose start spending more time in the shade, in cool water and in locations with cooling winds. They also frequently move to higher elevations.  When it gets really hot, they stop foraging for food during the one season they have to bulk up.

Not only will their chances of survival during the coming winter be compromised as a result of this, but successful reproduction is far less likely. In addition, heat stress can cause lowered immune response which leaves the affected animals more vulnerable to disease and parasites such as winter ticks and brainworm. Adding to these challenges, the make-up of woody plant species in boreal forests will also be affected by warmer temperatures, which in turn will affect both the browsing choices and the availability of shade for Moose.

It is theorized that within the next 100 years temperatures will rise on average 9 – 13°F. in winter and 6 – 14°F. in summer (New Hampshire Fish & Game).  On top of that, Maine, Vermont and New Hampshire are at the southernmost part of the Moose’s range. The future does not look bright for the largest member of the deer family in the Northeast.

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Green Herons Starting To Migrate

8-24-18 green heron2 20160916_0770Green Herons breed throughout the eastern half of North America.  After their nesting season is over they tend to wander, often to more favorable foraging areas. This dispersal merges gradually into a protracted fall migration for birds in the Northeast, beginning around the end of August, with most birds having left by mid-October.

Most Green Herons from eastern United States migrate south to winter along the Gulf of Mexico, Florida, Caribbean islands, Mexico, through Central America to northern South America.   We usually see our first Green Herons returning in mid-April, earlier than other herons.  This may be due to their crepuscular feeding habits, which gives them a longer span of time to feed each day.

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Second Brood of Snowberry Clearwing Moths In Flight

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Clearwing moths are strong and fast fliers with a rapid wingbeat, like the other members of the Sphingidae family. Most species in the group are active at dusk and feed much like hummingbirds, hovering in front of a flower and sipping nectar through their extended proboscis.  In most species, the larval stage is called a “hornworm” because the caterpillar’s posterior end has a horn-like appendage protruding upward.

Like its close relative, the Hummingbird Clearwing (Hemaris thysbe), the Snowberry Clearwing (Hemaris diffinis) is a day-flying moth, has transparent wings and is a mimic.  While they both hover at flowers, the Hummingbird Clearwing is said to mimic a hummingbird, while the Snowberry Clearwing is considered a bumblebee mimic.  To distinguish these two clearwings, if it has black legs and a black band that crosses the eye and travels down the side of the thorax, it’s a Snowberry Clearwing.

In addition to thistle, adult Snowberry Clearwings feed on honeysuckles, snowberry, hawkweed, lilacs and Canada violets. (Thanks to Barbara and Knox Johnson for photo op.)

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Eastern Gray Squirrels Swimming

e-gray squirrel swimming by Erin 2_H6A2563 copy (002)Imagine coming upon a stick floating in a large pond only to discover the “stick” had a head and tail and was making a beeline for the shore.  The fact that an Eastern Gray Squirrel (Sciurus carolinensis) had paddled half a mile to get from one shore to the opposite shore of a pond shouldn’t have come as such a surprise, as this rodent has a long history of migratory swimming behavior, but it’s such an incongruous and unexpected event that it made my companion and me initially question our eyesight and then laugh out loud.

Historical reports suggest there have been many massive Eastern Gray Squirrel migrations in the United States, beginning in 1749 in Pennsylvania.   Records show the state paid three cents for each squirrel killed; over 640,000 squirrels were turned in for bounty.  One migration from Wisconsin in 1842 lasted four weeks and involved a half billion squirrels. Because of the numerous squirrel migrations, John James Audubon was erroneously convinced that the squirrels on the move were a separate species from the Eastern Gray Squirrel and gave them the scientific name Sciurus migratorius. (This proved to be inaccurate.)

During the 1800’s, thousands of squirrels would periodically move en masse across roads, fields and forests, and swim across lakes and rivers (including the Mississippi and Connecticut Rivers) in an effort to disperse. The consensus is that these mass movements were a response to local food conditions. They occurred mostly during the month of September following a year in which there was a large production of food (acorns).

The most recent mass migration of Eastern Gray Squirrels in eastern U.S. occurred in 1968, when a bumper crop of acorns in 1967 was followed with a corresponding bumper crop of young squirrels in 1968. By fall, as the first litter of the year left the nest, there was a severe shortage of food. As a result, massive numbers of acorn-eating squirrels dispersed in search of food.

One Eastern Gray Squirrel swimming across a New Hampshire pond does not a migration make, but it might not be a bad idea to keep an eye out for excessive numbers of paddling squirrels and/or road-killed rodents come September. (Photo by Erin Donahue)

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Viceroy vs. Monarch

8-18-18 MONARCH vs. viceroy1To clarify yesterday’s post on mimicry, here are the Viceroy and Monarch, side by side. Note the horizontal black line across the hindwings of the Viceroy.  The (larger) Monarch lacks this line.

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