(CN) — The Kirtland’s warbler songbird has recovered sufficiently to be removed from the endangered species list, but the island marble butterfly, which lives only on an island in northwest Washington, should be protected, the U.S. Fish and Wildlife Service said Wednesday.
The Kirtland’s warbler is a small songbird that lives in very specific types of pine forests in the Upper Midwest. It was listed as endangered in 1967, just a year after the Endangered Species Preservation Act was enacted.
The warbler nests in young jack pines that grow after wildfires. Their population has been preserved partly though controlled burns that create more habitat for them. Its population has been slowly increasing, from 1,000 pairs counted in 2001 to more than 2,000 counted in 2012.
Fish and Wildlife is seeking public comment on the proposal to delist the warbler. It said a strong coalition of conservation groups have helped the bird recover, and continued work will be needed even if the bird is delisted.
“The general guidance of the recovery plan has been effective, and the Kirtland’s warbler has responded well to active management over the past 50 years,” the agency said.
“The primary threats identified at listing and during the development of the recovery plan have been managed, and commitments are in place to continue managing the threats. The status of the Kirtland’s warbler has improved, primarily due to breeding habitat and brood parasitism management.”
On Wednesday, the agency proposed listing the island marble butterfly as endangered.
The butterfly is found on the San Juan Islands in northwest Washington state. It is creamy white with greenish-yellow marbling on the underside of its wings.
If listed, the government would designate 812 acres on one of the islands as critical habitat for the butterfly.
The butterfly was historically found in Canada, but the last known specimen from there was collected in 1908. The species was rediscovered on San Juan Island 90 years later, and the population has been in decline for a decade.
Many culprits are blamed for the loss of habitat, including ”road maintenance, mowing, cultivation of land, intentional removal of host plants, improperly timed restoration activities, development, landscaping, deer browse, and livestock grazing,” the agency said.
The Xerces Society for Invertebrate Conservation and other groups petitioned the agency to list the island marble butterfly, and Xerces planned to sue when the agency did not finish a finding on the petition in a timely manner.
The agency settled with Xerces and added the species to a list of candidates with a high priority.
The National Park Service has targeted the butterfly for help for a decade, collecting and rearing eggs and establishing habitat patches fenced to keep deer out.
“These efforts will be crucial to establishing new populations of island marble butterfly in the future, but the achievement is too recent for their effectiveness to be evaluated, especially in the context of the extensive, ongoing habitat loss from changing land use, changing agricultural practices, and other factors that inhibit recolonization,” the agency wrote.