Kenn Kaufman couldn’t afford the boat ticket at Rockport, Texas, that would take him to see the world’s 49 remaining Whooping Cranes, so he thumbed a ride to the observation tower. From his vantage point, he could see the large, white birds far off in the distance. They appeared almost ghost-like against the dull brown of the refuge’s grass. Maybe their spectral appearance was the light, or maybe it was their brush with extinction. Thirty-five years earlier, their entire population had been reduced to only 28 birds. Recovering the species to a stable level was thought to be nearly impossible.
The year was 1973. Rachel Carson’s Silent Spring had been published just a decade prior. Its publication precipitated the ban of DDT in 1972, a toxic pesticide that had decimated bird populations since its introduction in 1945. Pelicans, eagles, falcons, and ospreys were some of the hardest hit by the chemical. Eskimo Curlews, once the most numerous North American shorebird, hadn’t been seen in a decade, and Ivory-billed Woodpeckers and Bachman’s Warblers were both teetering on the precipice of extinction. And in the midst of this, a 19-year-old Kenn Kaufman was hitchhiking his way across North America in an effort to set a record for the most bird species in a single year.
“We thought we were going to lose them”, said Kenn, now a Field Editor at Audubon Magazine. “Brown Pelicans, Bald Eagles, Peregrine Falcons, Ospreys – their numbers were just so low in the 70s.”
Now, a paper published in Science reports a colossal loss of 3 billion, or 29% of North American breeding birds since 1970. The scale of this decline has been hinted at increasingly by the scientific community. Each year, incomprehensible numbers of birds are killed by cats, window and powerline collisions, and pesticides. The losses are staggering.
According to the Breeding Bird Surveys (organized bird surveys done by volunteers across North America since the late 60s) used in the study, birds that live in the prairies have experienced some of the steepest declines; over half of their total population has disappeared. The native grasslands they require for nesting are a composite of species that together create a structure much like a forest. It isn’t intuitive, but grasslands are not all the same. In a native prairie, there are short grasses, tall grasses, bunch grasses, single-stemmed grasses, and all of the wildflowers growing among them. A pasture planted with introduced grasses typically only has a couple of species, and a structure that is more like a planted pine plantation – sterile underneath the canopy – than like a thriving woodland. And unlike reseeding a lawn or a hayfield, a native grassland won’t just grow back over a summer. The grasses are adapted to dry conditions, and so they grow slower and less competitively, at least in the short-term, than invasive species. Once native prairie is tilled, it becomes exceptionally difficult and expensive to restore.
The prairie is also one of the most agriculturally productive regions. Consequently, around half of grasslands have been cultivated, only about a third of native prairie remains, and 50-90% of wetlands in the same area have been drained. And much of this development is concomitant with pesticide application. The large-scale impact of pesticides on insect populations is hard for scientists to measure, but it can be seen in the birds that eat them. Aerial insectivores are birds that eat flying insects and, according to the same study, have declined by 32% since 1970. Different aerial insectivores use different habitats, nest in different parts of North America, winter in different parts of the hemisphere, migrate at different times of the spring and fall, but all of them eat the same food the same way. The guild-wide decline is a strong indicator that, while habitat loss, climate change, and land-use changes all have an impact, it is the loss of insects that is the primary factor for the loss of this group of birds.
“In ’71 or ’72 I was hitchhiking through southern Florida”, Kenn said, “and I called up a local birder, Allan Cruikshank, on a pay phone. I asked him where I could find the Dusky Seaside Sparrow. He told me where to go, and I found something like three singing males.”
The Dusky Seaside Sparrow, a species with a tiny range along the eastern side of Florida, never had a large population. Development of its shoreline habitat had reduced its population even further. Then, in 1973 taxonomists decided it was not distinct enough to be its own species and lumped it with the other seaside sparrows (Scott’s and Cape Sable) into a single species. The decision proved to be its death knell. Birders, no longer needing it for their species checklists, largely forgot about it. The few marshes it could still be found in were either flooded or drained, and its extinction was announced in 1990.
“I knew the taxonomic change was happening while I was doing my Big Year and that it wouldn’t count, but I still went to see it. It was still a cool bird”, Kenn told me. “Now, I think about going to those Indian River marshes and getting to see this really distinctive form of Seaside Sparrow, and I feel a sense of melancholy that it’s no longer there.”
Of course, it isn’t all bad news. Waterfowl populations have increased by 56% since 1970. This can largely be attributed to, ironically enough, waterfowl hunters. Strategic conservation efforts for waterfowl by game managers and non-government organizations have led to overall waterfowl increases. Likewise, raptors have shown a dramatic increase of 200% in the same period. Brown Pelicans, Bald Eagles, Peregrine Falcons, and Ospreys were all removed from the Endangered Species Act within the last 25 years. And Whooping Cranes are now, remarkably, a growing population of over 500 individuals.
“If you take a boat tour from Rockport now, you can see the Whooping Cranes on the edges of people’s yards!”, Kenn said, “The Whooping Crane, the Brown Pelican, the Bald Eagle, the Peregrine Falcon, the Osprey, the Kirtland’s Warbler, these are examples of the fact that a concerted conservation effort will work if we get there in time. And, sadly, the Dusky Seaside Sparrow is an example of something we didn’t get to in time.”
These successes show what might be. But if concerted action is not taken, declines will continue. Ecosystems will lose components, eventually breaking down to a non-functional state. Species will be lost forever. Habitat loss continues to be a major contributor to these losses, and infrastructure, invasive species (most notoriously, cats), pesticides, and climate change all compound to make surviving another season more difficult for birds. Organizations such as the American Bird Conservancy have been working to reduce these declines in both North and South America, The Nature Conservancy and The Nature Conservancy of Canada protect natural areas, Audubon has a strong network of hundreds of local chapters that provide a voice for conservation, and eBird and the Macaulay Library are online citizen science platforms that contribute data for monitoring bird populations and distribution. Supporting, joining, or participating in initiatives like these is a critical step towards turning the successes that might be into the successes that will be.