Which place has fewer birds: a city? or a cornfield?
When birders visit cities they often think, “There are no birds here.” This isn’t accurate, but I think so, too, until I realize there’s a very high quantity of birds but low quality — lots of pigeons, starlings and house sparrows. It’s the lack of diversity that prompts the comment.
Bird diversity is highest where the habitat provides a wide variety of food, cover and nesting sites. A 20-year study of abandoned fields on Long Island found that bird diversity increased with the foliage height. Since there’s not much foliage in cities the birds we find here are those who nest on or in buildings and eat human refuse or handouts — and the birds who prey on them (peregrines!).
Most songbirds eat insects and invertebrates which are hard to come by in the asphalt jungle. Even hummingbirds who sip nectar feed insects to their young. If you want birds you must have insects.
Places without insects are biological wastelands because they’re also missing everything that depends on insects, all the way up the food chain. Here’s a picture of a wasteland. There are no birds here.
I bet you’re thinking, “That’s not possible. There are plants in that cornfield. There have got to be insects and birds there too.”
No. There aren’t. Today in the U.S. we use more pesticides than we did when Rachel Carson warned us about them in Silent Spring.(1)
90% of the corn we grow is genetically engineered to survive the assaults of herbicides, fungicides and insecticides. This allows cornfields to be sprayed frequently(2) without hurting the corn. Corn seed is also coated with insecticide, neonicotinoids, that imbue the plant with poison.
There are no insects in cornfields, no birds, and no plants except corn. I was amazed when I found out about this at Cornstalks Everywhere But Nothing Else, Not even a Bee.
Not even a bee. Hmmmm…
(credits: photo of Pittsburgh from the Fort Pitt Bridge and a cornfield, both from Wikimedia Commons. Click on the images to see the originals. Today’s Tenth Page is inspired by page 620 of Ornithology by Frank B. Gill.)
A summer trip through the U.S. prairie states graphically illustrates the sheer magnitude of ” bug- free” landscape there. It must be 70— 80% of the total.
Hi Kate,
My experience as a birder has taught me there is a lot of success in timing and knowing what to look for at any given moment, even in the city.
Just last week in early evening I was walking through Avalon and as I was passing the elementary school I heard many Chimney swifts. I looked up and there where hundreds swirling over the school. I thought, they must be getting ready to roost in the school chimney. Once I located the chimney I just stood there and watched for 15 minutes with great joy how they swirled and eventually one after the other dove into the chimney. Other early evenings in different parts of town I will here the distinctive ping of a night hawk. I will look and look and then suddenly spot him way up there and say there he is!
So, let the city nose become background noise and tune those ears to catch the birds in their season.
Cheers,
Gene
Today I drove past many cornfields on my way to Marcy Cunkelman’s in Indiana County. Most appeared to be birdless even at the edges but one had swallows, sparrows and starlings. I was amazed to find a cornfield with birds but a hint as to why they were there may have been on the sign at the farm entrance: Conservation Farm.
Two more online resources:
Pesticide use is under-reported because seed treatments are not mentioned (May 2013):
http://blog.ucsusa.org/pesticide-use-is-actually-much-greater-than-reported-138
What do GMO seeds have to do with bee die-offs in corn belt? (May 2012)
https://www.commondreams.org/view/2012/05/16-6