Category Archives: Nature Notes

Can These Animals Fool You?

Many animals have particular patterns and colors that help them avoid predators. Some blend into the background or mimic an object like a leaf or twig, and some try to direct a predator’s attention to a less vulnerable body part. Test your visual skills with these tricky creatures.

American Woodcock

There’s a bird in this picture—can you see it? The American woodcock spends much of its time on the ground, where it’s well-camouflaged against leaf litter. Related to sandpipers, it uses a long beak to probe the ground for earthworms. Spot this secretive bird on an upcoming woodcock watch program.

TomZack_ZackStock Imaging

Gray Hairstreak

Heads or tails? The gray hairstreak has a false “head” on its hind wings that confuses predators. In this photo, the false head (complete with false antennae) is at the top. In a study on a related butterfly, the red-banded hairstreak, scientists found that jumping spiders were more likely to attack the fake head than the real one, enabling the butterfly to escape with its vital organs unscathed.

Treetop Bush Katydid

Can you see this insect? A nymph (or young) katydid is sitting on the largest milkweed leaf to the left. Many katydids mimic leaves, and though you’ll hear their loud calls during the warm months, they remain well hidden. Katydids look a bit like grasshoppers, but they’re more closely related to crickets.

Wood Frog

This frog spends much of its time on the forest floor, where it blends in with leaf litter. In the spring it lays eggs in temporary (or “vernal”) pools, calling for mates with a characteristic quacking sound. Having trouble spotting this frog? It’s near the bottom of the picture, a little left of center. Discover wood frogs and vernal pools in an upcoming program.

credit_Dave_Huth_davehuthdotcom

Eastern Screech-Owl

This small owl rests in tree cavities during the day. Its feathers blend in with the surrounding bark. Eastern screech-owls also nest in cavities, but they can’t carve into trees themselves, so they rely on woodpeckers and other cavity-creators.

credit_Richard_Johnson

Learn more about identifying these creatures with field guides from the Audubon Shop, and help kids record their sightings with this Nature Log for Kids. Happy searching!

Photo credits: American woodcock copyright Thomas Zack, ZackStock Imaging; gray hairstreak and treetop bush katydid via Rosemary Mosco, Mass Audubon staff; wood frog via Dave Huth, davehuth.com; eastern screech-owl via Richard Johnson.

Bird Songs Vs Calls

Red-winged blackbird copyright Jacob Mosser

Birds make a wide variety of vocalizations—from the harsh caw of a crow to the shrill screech of a hunting hawk to the ethereal fluting of a thrush. The wide array of sounds that birds make defies easy categorization, but for simplicity many birders and bird guides will refer to bird “songs” and bird “calls.”

What’s the difference, and which birds use what sounds? Matt Kamm, of Mass Audubon’s Bird Conservation team and co-author of the Breeding Bird Atlas 2, explains.

Songs

A song is a noise that a bird makes with a specific function, almost always one related to mating. Birds may sing to attract mates, ward off rivals from their territory, or bond with their mates and young. Songs tend to have a definite structure and rhythm, and are often repeated over and over again, sometimes with variations but usually on a single theme.

Birds that sing are usually those that breed in areas where visibility is low—dense forest or jungle, tangled shrubland, or open meadows where the grass grows tall. Sounds makes for a much more reliable signal than visual cues in these environments.

Birds that breed in open high-visibility situations, such as lakes, beaches, and rocky islands, have little use for song. This is why you will seldom hear of a heron, a duck, or a cormorant’s “song.” On the other hand, many sounds that might not sound musical to us are technically songs by this definition—the deep, resonant who cooks for you? hooting of the Barred Owl is one example.

Calls

A call, on the other hand, is much more flexible in terms of its usage. Many bird “calls” are short notes or phrases that birds use to convey everyday concepts. For example, a robin’s tut, tut means “danger is near,” and a Canada goose’s honk while migrating means “follow me!”

Many mother birds will use short chips or chirps to keep tabs on their young while foraging together, keeping up a constant chorus of “where are you?” and “here I am” so that families don’t get separated in the dense forest or scrubland.

Some birds have calls that not only warn others of danger, but have different alarm calls for different predators. The very flexible chick-a-dee-dee call given by black-capped chickadees can be used to communicate danger, and some research suggests that the number of dee notes increases in proportion to the danger of the perceived threat.

Start Listening

Many birds have both a song and several calls, and some birds sing multiple songs. Most birds sing primarily during breeding, but some (such as cardinals and house finches) are singing even now, and many birds will sing during spring migration.

Try listening to the birds outside to see if you can distinguish which is which. And tell us what you are hearing in the comments!

Photo © Jacob Mosser