Another gray day. But the wind is not blowing. As we pull into the driveway, there is bird motion to our left . . . and there go two doves. But they aren't quite right to be mourning doves. A bit too large. Note the tails -- not narrow and pointed but squared off with a broad white band. In flight, I can see that the white is on the outer edges of the gray tail. But more are in the driveway . . . I count 14! They all land in the cottonwood tree nearest the driveway. They're docile enough just sitting there, so I can get a good look. The undertail shows a great deal of white. Eurasian collared doves for sure!
These pigeon-like birds have become more common in our area over the past few years just as they have in many places. They were released in the Bahamas in the mid-1970s and were first documented in Florida in 1982. Now they are everywhere! Yet we know little about the effects on other birds. Cornell Lab of Ornithology did a study in 2009 analyzing Feeder Watch reports of the effects of Eurasian collared dove on similar species in Florida (mourning dove, common ground doves, white-winged doves and ordinary pigeons). Although the Eurasian collared dove is known to be aggressive, there seemed to be little effect on the other species.
In our area, I've not seen collared dove aggression but there seem to be fewer mourning doves. A comparison of sizes indicates to me that mere size could cause a decline of the mourning doves.
Mourning Dove:length=12 inches, wingspan=18, weight=4.2 ounces
Collared Dove:length=13 inches, wingspan=22, weight=7 ounces
It always amazes me to think about how small birds are and an inch or two can be very costly for the smaller bird. Note that the mourning dove is about half the weight of the collared.
Both birds may be found in the suburbs or in rural areas and their calls are similar with both sounding a series of "coo." The Eurasians' sounds are on the same pitch while the second call is higher and stronger with the mourning doves'. If you listen closely you can probably distinguish the two calls. And sadly, I hear Eurasian collared calls more frequently than our native mourning dove calls. More often than not, when I see a flash of white going into the neighbors' trees or gray birds with a squared-off tail sitting on a power lines, it's Eurasian collared dove. Yes, they are an invasive species!