Given that they have spread to at least 39 states, there appears to be only two places left in the lower 48--where they are now and where they are going to be. The impact they will have (or are having) on the native avifauna has yet to be determined, but one thing is certain, the Eurasian collared-dove has staked a claim in North America. And it likes the neighborhood.

The ECD pattern of invasion is not new. It took less than 50 years for the ECD to become ubiquitous to almost all of Europe in what has been called "the most impressive example?of the expansion of an animal species in zoogeographic history." In Germany alone, the ECD population grew from a handful of breeding pairs in 1945 to more than 1 million individuals in 35 years. In the United States, the progression has been similar, with populations in some areas increasing nearly 25 fold in only 10 years. The ECD is now found coast to coast, and is nesting from British Columbia in the north to U.S. border-states in the south.

Unlike many of the approximately 100 exotic bird species introduced to the United States, the story of the ECD arrival is fairly well documented. Following the burglary of a pet shop on the Bahaman island of New Providence in 1974, the shop's owner promptly released his entire flock of 50 ECDs after a few individuals escaped during the break-in. After establishing a wild flock, the liberated birds took only a few years to make the short flight to Florida. An abundance of backyard bird feeders and other year-round agricultural food sources did the rest.

Unfortunately, little more is known about the nature or implications of the ECDs' spread in the United States. Even less is understood about their ecology, habitat requirements or competition with native species. Of the limited data available, much is conflicting. For example, the Christmas Bird Count documents the presence of ECDs in 39 states, whereas the North American Breeding Bird Survey reports ECDs in only 19 states. "We don't have a good idea of how many Eurasian collared-doves there are in the U.S.," said Dr. Christina Romagosa, a researcher with the Center for Sustainable Forestry at Auburn University. ?

Romagosa and her colleagues have conducted most of the research on ECDs in the United States and have documented or collected what is known about the bird's life history in this country. She readily admits, however, that not enough is known about ECDs, their ecology, and how they interact with other smaller, native dove species. "Although we have observed large flocks of ECDs chasing off other dove species and even cardinals and red-winged blackbirds from feeding sites, that's not always the case. It seems to depend on the area and size of the [ECD] flock."

To date, the question of how ECDs might impact native dove species has been largely unanswered. Also, there is no documented evidence of nesting competition between ECDs and native doves. And despite Romagosa's observations of ECDs displacing other doves, research from Tennessee Tech University on the foraging competition between ECDs and mourning doves "did not indicate that collared-doves are behaviorally more aggressive or competitively more successful than mourning doves." This is particularly interesting, considering the study documented a 95 percent dietary overlap of the two species. Dietary overlap has been postulated by many as a way in which ECDs might outcompete mourning doves for food resources. To date, however, it seems that ECDs are restricted to human-dominated or agricultural landscapes that yield year-round food sources and ample nesting/roosting habitat. "You always seem to see ECDs where there is a house or agricultural field nearby," said Romagosa. "They don't utilize forage in forested areas, which is good for mourning doves."?? ?

"The general rule of thumb is, if you see an EDC, turn around 360 degrees and you'll see a house," said Johnathan O'Dell, Wildlife Specialist with the Arizona Game and Fish Department. "I haven't seen any real evidence of competition for food between ECDs and other doves, but they [ECDs] are highly adaptable to the wide food base in rural areas. For that matter, I've seen them eat dog and cat food."

In Arizona, O'Dell has noticed an additional potential impact of ECD colonization?their ability to hybridize with domestic ringed turtle-doves. Domestic doves, variants of the African collared-dove, have long been members of the North American avifauna, thanks to releases from?wedding ceremonies and disgruntled pet owners. The accepted belief of contemporary wildlife managers is that these released doves generally survive no more than two generations in the wild. ECDs are changing that. "What we're seeing is that the hybrids are reproducing in the wild and reverting back to the plumage of typical African collared-doves," stated O'Dell. "Right now, I think the hybrids will mostly stay in the lower four states of the Southwest, but who knows?" California and Florida also documented the wild/domestic dove hybrids.

As with information surrounding the species' status, ECD management is limited and inconsistent. Currently, the U.S. Fish and Wildlife Service (FWS) is doing nothing to track or document the ECD expansion in the United States. "They are not high on our priority list," said Todd Sanders, wildlife biologist with the USFWS Division of Migratory Bird Management. "We are not currently doing anything to monitor ECDs and are not concerned [about them] ecologically. Data suggest that they are not significant in terms of competing with mourning doves." ECDs are not included in the Migratory Bird Treaty Act because the FWS does not classify them as migratory. "They only migrate locally; we haven't seen anything large scale," said Sanders.

Accordingly, the ECD is not under FWS authority, so individual state wildlife agencies have the responsibility of managing ECDs. Given the lack of resources to conduct dedicated monitoring or management, most states have turned to the next-best option?recreational hunting. The use of hunting to manage ECDs is not new. Following the dove release in the Bahamas, local hunters began noticing these new birds and, by the early 1980s "organized dove-hunts were being held in late summer." At present, 23 states have opened the hunting season for ECDs. For the majority, ECDs are considered "bonus birds" that can be harvested without bag or possession limits during regular dove seasons.

"ECDs seem to be easier to hit because they are larger than the other dove species and they follow a more direct flight path," noted Romagosa. In Alabama, hunters have embraced the new hunting opportunities presented by ECDs and praise the dove's quality as table fare. Some states, such as Colorado, take advantage of the ECDs' reluctance to migrate by extending the ECD hunting season two months beyond the regular dove season; well after the native dove species have gone south. Arizona and Texas have maximized the benefits of the EDCs' robust population dynamics by allowing year-round hunting with no bag limit. The question remains, however, whether hunting will be an effective technique for managing ECDs given their propensity to thrive in suburban areas.

Also still unknown is whether the ECD will prove to be a viable and sustainable new game species or pose a biological threat. Considering its past, unprecedented dispersal and ability to nest year-round, produce three to six clutches a year, and utilize a broad forage base, there is no reason to believe that the ECD will not become a widespread, permanent and influential member of the North American avifauna. The ecological consequences of its arrival and persistence, if any, are unknown and unstudied. Until there is more knowledge or concern, the one undeniable truth about the ECD is that, as Romagosa observed, "There is no place they won't go." (mcd)