National study suggests Nova Scotia birds are under pressure
Posted Jun 22, 2019 11:06:00 AM.
This article is more than 5 years old.
The 2019 State of Canada's Birds Report issues a strong warning about the decline of diversity and abundance of the country's birds.
The report was issued by Environment and Climate Change Canada on behalf of the North American Bird Conservation and looks at the population trends of over 400 birds since 1970.
“Several broad groupings of birds across North America have experienced pretty significant declines over the last 50 years,” says Craig Smith, the Nature Conservancy of Canada’s program manager in Nova Scotia. “It's unfortunately a trend that seems to be expanding over time.”
The overarching reasons the study cites for why certain populations have declined, includes habitat loss, unsustainable agricultural practices, climate change and pollution.
The study finds the birds in most rapid decline are shorebirds, grassland birds and aerial insectivore birds, saying their populations have been cut by 40 to 60 per cent since 1970.
President of the Nova Scotia Bird Society David Currie says Nova Scotia is home to species in all of these broad bird groupings.
Birds known as aerial insectivores feed on flying insects, according to Currie. He credits the population decline of 59 per cent to fewer insects and unusual temperatures.
“It seems like most people around the world are noticing tremendous decreases in the number of bugs these birds rely on,” he says. “Insects depend on the temperature and if the temperature is changing the birds have trouble surviving because the amount of food isn't available for them.”
The study finds in the last decade, 80 per cent of bird species newly assessed as threatened or endangered in Canada, have been aerial insectivores or grassland birds.
To name a few affected in Nova Scotia, the province's population of chimney swifts was listed as endangered in 2007. In 2013, the barn swallow was added to that list as well as the bank swallow in 2017. The olive-sided flycatcher was listed as threatened in 2013 and in the same year eastern whip-poor-will was given the same status.
Currie adds the purple martin, an aerial insectivore species, at one time lived in Amherst but now no longer breeds in Nova Scotia.
“They are long gone, and it could very well be because of a diminished food supply,” he says.
The report says shorebird populations have decreased by 40 per cent nationally likely because many coastal areas and inland wetlands are being lost to coastal development and human disturbance.
“Habitat loss is really the problem facing piping plovers,” Currie says about the shorebird, listed as endangered in Nova Scotia in 2000. “There are only a few beaches in the province that can be inhabited and be successful for breeding piping plovers.”
In Nova Scotia it is believed only about 40 breeding pairs of piping plovers remain.
Canada’s grasslands have lost 300 million birds since 1970, or two out of every three birds, according to the study. Overall grassland species declined by 57 per cent in the last 50 years.
Currie says bobolinks are birds of open grasslands and hayfields that are having a hard time in Nova Scotia. He says they are threatened by hay moving that kills young and destroys nests.
“With changing temperatures and farming practises, it is much easier to get a few cuts of hay in a year and so bobolinks aren't doing so well because they don't have enough time to raise their young in these fields,” he says.
The study isn't all doom and gloom however. It does reveal that birds of prey such as the bald eagle, peregrine falcon, and osprey have recovered since the use of the insecticide DDT was banned in Canada and the United States in the 1970s, and in Mexico in the late 1990s.
“DDT had a well documented case of having an extremely negative impact on birds, particularly on raptors,” says Smith. “But that group of birds has increased over 100 per cent since we solved the DDT problem.”
Smith says the parallel message in the report is that there is hope.
“There are certainly precedents for major recoveries among wildlife populations and bird populations when major stressors and threats are reduced heavily or eliminated,” he says. “Nature is not in a fantastic state on the whole, but quitting is not an option. We have to keep going forward using the best information and tools we've got.”
