They say birds of a feather flock together, but it’s not always true. Sometimes, birds of a feather — birds of the same species — are separated regionally, may be divided along lines of habitat or migration patterns or display other differences that lead scientists to classify them as distinct subspecies. For example, the greater Canada goose is widespread throughout the continent, but the dusky Canada goose winters only in the Pacific Northwest. Such differences are fairly common, yet most assessments of the conservation needs of birds have been largely species-centric, even though different subspecies may be facing different levels of risk.
The American Bird Conservancy has bucked this trend with their recent study and resulting classification of risk levels among birds. It is the first study of its kind to include the full range of bird diversity throughout the entire U.S. and the first to rank subspecies. In addition, the study includes what it calls “habitypes” — birds that are nearly identical, but rely on different types of habitat to nest. For instance, one population of the marbled murrelet nests in old-growth forests, while another nests on the ground.
The resulting 1,826 birds were given a “vulnerability rank” using a methodology based on such factors as population trend, breeding distribution and threats to breeding. A rank of between four and eight qualifies a bird as “secure,” nine to 12 indicates “potential concern,” 13 to 16 categorizes a bird as “vulnerable” and 17 to 20 establishes that a bird is “at risk.”
The good news is that by finally including subspecies in the rankings, conservationists can get a much more complete picture — a birds’-eye view, if you will — of the state of birds’ conservation needs. It also may help future assessments, as today’s subspecies could be tomorrow’s species. By including them in current studies, it helps ensure that they will not be overlooked in the future.
The bad news is that only 15 percent of the 1,826 birds ranked as secure, leaving the majority of birds in U.S. in need of some level of conservation attention. Of the 30 percent that ranked as vulnerable and the nine percent that have been shown to be at risk, most are specialized species, relying on a very particular food or habitat and therefore lacking the flexibility to adapt to habitat loss.
One region’s birds seem to have it particularly tough. Half of the birds that are most in need are endemic to Hawai’i. Sadly, despite the risk they face, these birds — species like the palila and the Maui parrotbill — tend to receive less funding than their mainland counterparts.
American Forests is doing our part to aid in conservation efforts for threatened Hawai’ian birds by helping to restore their dwindling habitat. Through our Global ReLeaf project in Waihou Forest, we’re partnering with the Hawaiian Silversword Foundation and others to plant 6,000 trees in the Pu’u Wa’awa’a area by the end of next year. By restoring their habitat, we hope to see a revival in wildlife populations, including at-risk native bird species.