The 2009 State of the Birds report, released yesterday, is not a happy read. Over the last 40 years, bird populations in the United States have not been doing well, as a whole. There are a few hopeful signs here and there - some populations have recovered - but almost 1/3 of the species in America are endangered, threatened, or show signs of significant population declines. That's not good.
As bad as the situation on the US Mainland may be, it pales compared to the situation in Hawai'i. At the moment, 31 species of native Hawaiian birds are Federally listed as endangered or threatened. Several more species are considered to be candidates for listing. It is believed that 10 of the 31 listed species are actually extinct, and that 1 is extinct in the wild.
These species face a very wide range of threats. From the report:
Most of Hawaii's conservation crises result from the introduction of nonnative plants and animals, but climate change is a growing concern. The leading threats to Hawaiian birds include habitat degradation from trampling and grazing by introduced ungulates; nonnative predators (e.g., feral cats, mongooses, rats); nonnative plants and diseases; and bird diseases spread by introduced mosquitoes.
Most native birds are now largely restricted to forests above the mosquito line at about 5,000 feet, a haven that is expected to shrink as increasing global temperatures enable mosquitoes to survive at higher altitudes. In addition, rising sea level is projected to inundate important breeding sites for many species, especially for seabirds on the low-lying Northwestern Hawaiian Islands.
As of now, there are few signs that this situation will improve in the near future. What makes this extremely frustrating is that there are some things that can be done that could significantly improve the situation. Unfortunately, they're not being done on a large enough scale to have a substantial impact. That's unfortunate, because most of these measures are not that expensive.
One of the largest problems for the native birds is caused by pigs. There are large populations of feral pigs on all of the main Hawaiian islands. The pigs uproot and trample vegetation. This creates areas where invasive plant species can more easily gain a foothold. They also tend to provide more areas for water to collect, providing more breeding opportunities for the mosquitoes that carry many of the diseases that are devastating these species. A combination of increased hunting and fencing areas to keep pigs out can go a long way toward reducing this problem.
Hopefully, the report will spark more awareness of these problems, and stir some more substantial recovery efforts.