Tag Archives: birds

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

Bird Storm Prep

copyright Cheryl Rose

Photo copyright Cheryl Rose

Stormy winter weather could drive even the hardiest souls indoors. Our feathered friends don’t have central heating or a cozy fireplace to retreat to, though.

Fortunately, birds have a number of amazing adaptations and savvy strategies for surviving the worst that Old Man Winter can throw at them.

Mass Audubon’s Bird Conversation department shares ways birds cope with storms.

Under Pressure

A common recurring theme in folklore is that animals can sense coming changes in the weather. In the case of birds, at least, this appears to be the case. Birds can sense a coming storm because of their sensitivity to changes in barometric pressure.

This gives them time to forage for enough food to last them through a period of inactivity and to find shelter. The exact method by which birds can detect changes in pressure while we humans cannot is not fully understood, but a special organ in the middle ear called the para-tympanic organ (PTO) is believed to play a role.

Hunker Down

Just like people, many birds seek shelter from bad weather. High winds and soaking precipitation make for bad flying conditions, so most birds choose to sit tight and wait out the storm when they can.

Many birds, like chickadees and woodpeckers, will seek out the same tree cavities and other nooks that they might use for nesting during other times of the year. Other birds will retreat into dense foliage, especially evergreen foliage that retains a protective shield of leaves even in winter.

Staying Warm

Some of the hardiest birds will continue foraging even through snow, rain, and freezing conditions. It’s not unusual to see huge flocks of gulls standing or sitting on frozen ponds during days when the cold and wind drive most humans indoors.

Birds are warm-blooded, just like humans, and many of them maintain a higher body temperature than we do (a few degrees above a hundred is within the typical range for many birds). So how do they stay warm? Birds have some ingenious tricks:

1. Heat Exchange
Many birds (like gulls, ducks, and geese) that stand or sit on ice or freezing water for long periods have a counter-current heat exchange system running through their legs. Simply put, warm blood being pumped from the body’s core in arteries passes very nearby cold blood traveling back up through the veins. Heat diffuses from the arteries to the veins, warming the blood up before it enters the bird’s core and cooling the blood down before it reaches the foot.

By keeping their feet just above freezing, birds vastly reduce heat loss. A bird’s feet are very spare structures: not much but skin, bone, and sinew. This simple structure, devoid of energy-hungry tissues, helps the foot survive cold temperatures without permanent harm.

2. Functional Feathers
Anyone who has worn a down jacket knows how effective feathers can be at trapping air and keeping you warm, and birds use this insulation to create pockets of warm air next to their skin. When an exposed foot or leg does get too cold, many birds will pull it up into their feathers to sit next to the body and warm up.

They may also tuck other featherless areas (such as the bill) under their wing to minimize heat loss that way. Even small perching birds like juncos will use these strategies—a foraging junco will often stop and crouch for a few seconds, bringing its feathers down over its feet and allowing them to warm up. Look for this behavior the next time you’re out on a cold day.

3. Deep Sleep
Many birds that have very high metabolisms cannot survive New England winters, so they migrate to warmer climates. But what happens when a freak cold snap or an unseasonable storm drops the temperature beyond these birds’ comfort zones? Birds like swifts and hummingbirds have the ability to enter a deep sleep called torpor.

Much as with hibernation in mammals (in fact, hibernation is a type of torpor), a torpid bird uses much less energy and can survive a drop in its body temperature that would quickly result in death if all systems were still trying to run full-tilt. Once the storm or cold snap passes and the temperature warms up again, the torpor ends and the bird can resume foraging.