There was a time when I considered the mourning dove to be too commonplace and familiar to be worthy of much attention. All of this changed one winter when I began to notice that some birds at my birdfeeder had frostbitten toes and missing toenails. I looked into the matter and learned that mourning doves were originally a southern bird, and they’re not well adapted to our harsh winters. Suddenly, the mourning dove went from being ordinary and familiar to being unusual and interesting. I began to wonder what other secrets the mourning dove had to share.
When Europeans first arrived in the New World, mourning doves probably existed only in scattered locations throughout North America. But that would change. As the settlers modified the land to suit their needs, they ended up suiting the mourning doves’ needs as well. Both humans and doves like open and semi-open habitats: neighborhoods, parks, open woods, grasslands, and farms.
Today, the mourning dove holds the distinction of being the only native North American bird to breed in every state, including Hawaii. Their U.S. population is estimated at more than 400 million. Despite their numbers, their lives tend to be short and difficult. In any given year, more than half of the adults and two thirds of first-year birds will die. Nationwide, hunters take more than two million birds annually, though the mourning dove is not a legal game bird in Vermont or New Hampshire. Around here, predators and bad weather are the limiting factors.
While observing the birds, it is possible to tell the difference between males and females, although the difference is subtle. Males are a little larger, their breasts are rosier, and their heads are a more iridescent and brighter blue-gray. If you’re watching a nest, note that males do most of the incubating from mid-morning to mid-afternoon, while females typically take to the nest in the early morning, evening, and night.
As is the case with most members of the dove family, females lay two eggs. Both male and female provide their hatchlings crop milk, a rich mixture of cells sloughed off from the crop wall. Crop milk is the consistency of cottage cheese, and is extremely nutritious, having more protein and fat than mammalian milk. On crop milk, the young grow quickly fledging in about 14 days. But what may be more interesting than what is fed to hatchlings is how dove hatchlings eat. Instead of mom and dad placing food into the hatchlings’ gaping mouths, the opposite happens. Parents open their beaks, and babies stick their heads into the open mouths to consume food right from the parent’s crop. Young doves feed this way on both crop milk and seed. In the Northeast, mourning doves may raise up to three broods a year, although two is more common.
While mourning doves are common at the bird feeder all year round, the doves you see in winter are not the same as the ones you see in summer. Mourning dove’s migration is a complicated affair called “differential” migration and is related to a bird’s age and sex. They begin to move south to the mid-Atlantic and southern states in late August and early September. The young leave first, then the females, and finally the males. Some birds, most of them males, don’t migrate at all but remain in the north. If you look closely at the mourning doves at your winter feeders, you will find that they are predominantly males. It’s worth it to these males to brave bad weather and frostbitten toes to get a head start on establishing a good breeding territory early in the spring.
If you’ve ever startled a mourning dove, you undoubtedly caused it to blast off into the air from its perch, making a whistling sound as it goes. This high-pitched whistle – sometimes called a whinny – does not emanate from the bird’s syrinx; rather, the high-pitched noise comes from the bird’s powerful wings. It is believed that the whistling is a built-in alarm system, warning others that danger may be near, while simultaneously startling a would-be predator (and giving the dove the precious seconds it needs to make its escape).
The more I learn and the more I look, the more I see that the common mourning dove is not so common at all. This winter I’ll be watching them very closely; there may yet be more secrets to learn.
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