This is a slightly different form of the diary series I've been doing so far this spring. Instead of talking about the birds I've seen, I'm going to talk about the ones I haven't.
And the reason I'm doing this, it to warn and alert people that we are in for some serious problems due to environmental degradation caused by man, and his unexpected partners. Join me below while we look for what we've lost, in the hope that we can stop before we lose too much.
Met a woman while birding last week in Westchester county, NY. She asked me if I'd seen any wood thrush- I told her no, I'd seen their relatives the veery just a minute earlier, but no wood thrush. She introduced herself as being far more interested in botany, particularly the wild undergrowth plants that we see in the northeastern mixed forests.
My reply was "what undergrowth"? While not my main interest I've hunted for wild flowers and plants in the past, getting more than my share of mosquito bites while photographing (many years ago, before the age of digital) wild iris, orchids, lilies and trillium. It was never more than a sideline, there is just so much variety and complexity that to be anything more than a causal observer would take too much energy.
She commented that the exploding population of deer in the area had pretty much eroded all of the ground cover, eliminating the habitat needed for many species such as the wood thrush.
It made me think- in recent years they've all but eliminated breeding populations of hooded warblers, Connecticut, Kentucky, worm-eating, golden-winged, black and white, and yellow-throated warblers. Most of these species are arboreal, but they do spend a lot of time near the ground. The black and white makes their nest at the base of a tree, and losing ground cover would make them exposed. Ovenbirds (a very common warbler, but in decline) are named after their nests which resemble Dutch ovens build on the ground.
Thrushes are birds that live on the ground, mostly making their nests in trees. Among the thrush family are the various "thrush", robins, bluebirds, thrashers and their close cousins the mockingbirds, and catbirds. Most have fantastic voices, among the best in the bird world.
But they're dying off. I've seen estimates of almost 90% reductions in wood thrush populations since 1960! That is a frightening trend, which unless reversed could endanger the very existence of the bird. Now it isn't all caused by deer- that is only a minor cause, but it does effect. More and more land is being developed for McMansions as cities sprawl deeper and deeper into the exurbs. There are more species that are being effected by our spread- black bears are now commonplace in suburbia as we move more and more into their territories. It isn't like we're going to stop expanding, and while they aren't in trouble it doesn't take much for a species to feel the bite. Many larger mammals worldwide are in threat of extinction due mostly to habitat loss.
I can't help but face the fact that given the choice between living in bigger and better homes, or making home for wildlife, people will chose themselves. They ain't building land anymore, and the problem is, what land we have is being destroyed.
We've had several diaries detailing the horrors of mountaintop excavation of coal. While you might not imagine the severity of the problem, it will possibly cause the extinction of perhaps the most beautiful of all Dendroica warblers, the cerulean. Loss of habitat is also hurting the stunning gold-winged warbler (that and hybridization with the blue-wing) Insert obligatory blue wing photo here...
Habitat loss is great in Appalachia, but the greatest loss has been on the gulf coast. From Galveston to Naples, more than 90% of the coast has been developed, eliminating prime breeding land and rookeries as well as staging areas for migrating birds. In order for birds to reach their nesting sites in the US and Canada, they need to fly from their wintering grounds in Mexico, Central America and the West Indies through the southern half of the nation. A great many birds fly through the West Indies, using the Everglades and the Space Coast as their first stops. Declining habitat and drought is causing them to leave without fully refueling, weakening them along the way. For birds flying from the Yucatan to the Gulf states, they begin their trip around sundown and fly non-stop for between 15 and 24 hours. If they can't refuel immediately at the barrier islands and parks, they will die of exhaustion after they make landfall. These birds often require a few days of rest before going on, and without sufficient food they won't make the trip north healthy enough to breed and defend territory.
Another problem: the significant change in climate in recent years has accelerated tree growth and the seasonality of insects needed for bird survival. Insects are now hatching a few weeks earlier than they did only a few decades ago. So the bountiful caterpillars that fed billions are now speeding up their development. Unless the birds react and move their migrations and nesting cycles in time, they will have less food available, which will mean fewer birds.
And conversely, this will mean more insects. Songbird populations can explode after a good summer, to as much as three or more times higher than in the spring. These birds as they slowly migrate south devour hundreds of billions of insects each day, ridding us of pests, nuisance species, and potential disease carriers. Remember that insects can multiply amazingly fast, while their predators are slow to increase their numbers. The fewer birds, spiders and bats (and they've got their own problems) the more biting insects, the more diseases they pass to us. Birds and other insect predators reduce losses to our crops, and help reduce the need for pesticides. An owl box filled with nesting owls can eat several mice and rats each day, dramatically reducing losses and almost eliminating the need for traps and chemicals in the environment. Remember that what we don't have to spray, we don't have enter the food chain and water supply.
Now for the bad news- I don't think there is much we can do about it. This isn't a case of conservation or personal change, this requires major environmental remediation. We have to stop ripping apart the Appalachians, reduce logging in Boreal Canada, eliminate invasive beetle species in BC and the west. We need to buy up more land in sensitive areas and prevent development along shorelines. This takes money; huge, almost obscene amounts of it. I am so grateful to the people who've live in and ran the NYC area because they've set aside so much land as natural habitat and preserve, but there is only so much you can do in one isolated pocket. We have very little beach development, with most of the Atlantic and Long Island sound still available for wildlife. There are tons of millionaire's home dotting the coast, but they aren't as intrusive as large land development, and these people don't cover every inch of their property with buildings. We have to do what we can to remind politicians on both the national and local levels that parks and watershed areas protect our population centers from natural disasters. They ameliorate the effects of floods and storms, help reduce the effects of water pollution, and in general improve the health of local communities, both physical and emotional. We NEED parkland, we need nature, we need to feel the earth at our feet, not asphalt or concrete.
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This morning was Central Park's turn to see if it could underperform. It didn't! Personal record numbers of ovenbirds, with at least 25. More than 50 redstarts, nearly that many common yellowthroats, at least 25 black and white warblers, very strong double-digit numbers for both Louisiana and northern waterthrush. At least a dozen magnolia, nearly that many black-throated blue warblers, four Canadas, three beautiful chestnut-sided warblers, a single yellow, blue-winged, Tennessee and northern parula. I'd say more than 200 warblers seen, and many more heard that I didn't bother with. I turned my back at so many, trying to find the rarer species. Tons of thrush, including singing wood thrush and veery, quiet hermits, and a single grey-cheeked. Saw a least flycatcher (all flycatcher numbers have been poor, but they are late migrators) and heard hawking from many angles- Pale Male must have been busy. Had a very close female scarlet tanager (but sadly no male) as well as a few Baltimores. The weather was beautiful.
My best bird of the day was a catbird that seemed to want to be handfed. I sat down next to him and started talking, cooing, and generally trying to reassure him that I wasn't looking to make him into dinner. Spent about two minutes with me before I got bored, stood up, and walked away. They are such intelligent and curious birds, and when you look into their eyes you can see there's somebody in there. Another species that is declining due to habitat loss, but they aren't in that much trouble yet. Some birds are expanding their range due to warming, and the conversion of farmland into grassland and parks. There are more blue-winged warblers, more chestnut-sided warblers, and more mockingbirds than before. Unfortunately cowbirds are doing well, as are chipmunks and squirrels, which all contribute to declining songbird populations either through nest parasitism or depredation. Add to this the proliferation of invasive species that crowd out natives (not just birds- fish, amphibians, plants and insects) and our natural heritage is in trouble.