Although it looks like a caterpillar, this larva is not going to metamorphose into a butterfly or moth. This is because it is a sawfly larva, and is closely related to bees and wasps. (It gets its name from the adult female’s saw-like, egg-laying ovipositor that opens like a jack-knife from the tip of her abdomen.)There are several ways to distinguish between these two types of larvae (sawflies and butterflies/moths). While both have three pairs of true legs on their thorax, caterpillars (larvae of moths and butterflies) have up to five pairs of prolegs (fleshy structures that resemble legs) located on their abdomen behind their true legs, while sawfly larvae have six or more pairs. A closer look at the tips of the prolegs on caterpillars will reveal tiny hooks called “crochets,” which are lacking on sawfly larvae prolegs. Sawfly larvae also exhibit distinctive behavior. If you see something that looks like a caterpillar feeding along the margin of a leaf and it rears up its hind end when disturbed (perhaps to frighten predators), chances are great that you are looking at a sawfly larva.
There are only about three short weeks in the late spring when the blossoms of Yellow Lady’s Slippers grace our woodlands and wetlands. The production of an orchid is a complicated process. If pollination and fertilization are successful, hundreds of thousands of some of the smallest seeds of any flowers are scattered by the wind. The seeds of Yellow Lady’s Slippers (and other orchids), unlike those of most flowering plants, contain no food for the seedling plant. In addition, the coating surrounding the seed is extremely tough, so much so that the seed can’t germinate until Rhizoctonia fungi digest the outer coating, which allows the inner seed to access soil nutrients. This can take two years or more and then it may take another few years for the plant to produce a flower.
We’re approaching the peak of the black bear mating season in late May and June, and there’s no better time to look for bear sign than right now. Both male and female bears increase their movements during this time of year. According to the North American Bear Center, males have mating ranges 10-15 miles in diameter and each mating range contains 7-15 female territories. During May and June, both sexes, but particularly the males, mark their territory by leaving their scent on trees, shrubs, telephone poles, sign posts, etc. They do so by thrashing around, rubbing their shoulders and neck against trees and poles, biting and clawing them and urinating on young trees and bushes that they straddle as they walk along. Often the tops and many branches of saplings are broken off, as is evident in this photograph taken recently by Alfred Balch of Lyme, NH.
The House Sparrow’s (also known as English Sparrow) reputation leaves a bit to be desired. It is an introduced species which has thrived in North America to the point where it is considered a nuisance species and an agricultural pest. Its tendency to displace native birds such as Eastern Bluebirds and Tree Swallows from nest boxes does not endear it to many bird lovers. However, one has to acknowledge the fact that male House Sparrows are the exception rather than the rule when it comes to parenting. Males help choose the nest site, build the nest, incubate the eggs, brood and feed the nestlings and keep the nest clean by removing the nestlings’ fecal sacs. That’s more than can be said for some of our most admired species, such as male Ruby-throated Hummingbirds, which disappear shortly after copulation.
Even though it snowed in Vermont this weekend, there is something else white and fluffy that is also being blown about, and it doesn’t melt when it hits the ground. The tiny white bits of fluff that are floating in the air are the seeds of aspens (also referred to as poplars), primarily Bigtooth Aspen (Populus grandidentata), that are borne in capsules that develop along a 3 to 6-inch dangling stem. These former flower clusters, and the capsules and seeds they developed into, are referred to as catkins. The capsules split apart when the seeds are mature, releasing the cottony-tufted seeds that are well-designed for dispersal by the wind. Looking into the fluff-filled sky, it’s not hard to believe that a single Bigtooth Aspen tree can produce over a million seeds.
Yesterday’s mystery duckling was a Hooded Merganser. Wood Duck and Hooded Merganser ducklings are very similar, however Wood Duck young possess a dark, horizontal line behind their eyes which Hooded Merganser ducklings lack. There are several ducks that nest in tree cavities in New England, including Wood Ducks, Common Goldeneyes, Common Mergansers and Hooded Mergansers. Hooded Merganser ducklings leave their nest cavity within 24 hours of hatching, in response to their mother’s calls below. They jump/climb up the wall of the cavity and hurl themselves out of the tree. Depending on where the tree is located, they fall either onto the ground, where they bounce like a tennis ball upon landing, or straight into the water. Hooded Merganser fledglings have been known to fall as far as 50 feet to the ground and then walk as far as half a mile with their mother to the nearest body of water.