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Since 2008, I’ve tracked a killdeer population at the golf course where I work. Here are my observations, starting five years ago, with updates.
The sliver of moon and the sweep of stars in the country sky lit the curves of the golf course as I piloted the small jeep at 5 am.
The jeep has a rake attachment that I drag through each of the 53 golf bunkers, which are parking spot-sized depressions filled with sand. After fluffing the sand with the jeep, I hand rake the edges.
After doing this for ten years, I know every bump, even in the dark, so I am driving at top speed, about 15 miles an hour. A dim headlight lights up my path.
I am roaring up a hill, headed into the bunker, like Steve McQueen in the car chase scene in Bullitt, when suddenly there’s a white explosion in front of my face along with a loud screech. I swerve the bunker rake so severely that I almost turn it over.
I stopped the bunker rake next to figure out what the hell had happened. Then I saw a killdeer, a robin-sized bird on twig-thin legs, strutting around on the bunker sand, probably proud it had routed me. It had masked raccoon-like markings around its eyes, a needle like beak, and alternate striping of brown and white, almost as if it was dressed in tweed.
I approached it on foot and it changed tactics, thrusting out an apparently damaged wing at an uncomfortable angle, and staggering away.
Then I saw the killdeer was defending 4 mottled eggs in a depression scraped in the sand, the size of a cereal bowl and not as deep. So I raked around the nest, while the killdeer complained at me from the side. I crammed a large stick into the bunker next to the nest to alert other workers not to run over the nest.
In that year of 2008, the killdeer excavated nests in the sand bunkers, and also scraped nesting spots in the bark dust under benches where golfers sat.
The killdeer are characters. Any time someone tried to approach their nest, they would fake an injury, twisting a wing out to their side, and stumble away from their nest.
After baiting the potential predator to about 30 feet away from the nest, the killdeer would suddenly heal and fly away, its tail feathers erect in the avian version of a stiff middle finger.
Even if you ignored the broken wing trick, you might not find their nest. The eggs’ colors blended with the bark dust. I would stand there stupidly, the nest inches from my boots, and not see it for minutes.
There were no birds there when the course opened in 1998. I wondered what it meant for the killdeers’ future to take up life on a golf course. I kept track of how many killdeer I spotted, where they were, where they nested, and how many eggs hatched.
I was concerned because the golf course poisoned the weeds, bugs, and the grass diseases that festered within molds and funguses and mosses. The killdeer were always eating bugs.
The lurking cats, coyotes, hawks, skunks, raccoons, possums, crows and snakes could also eat killdeer eggs or the killdeer themselves. Was the golf course luring killdeer to destruction? The biologists call that possibility a population “sink.”
That April I counted 5 killdeer couples scattered around the course. The male bird would scrape a shallow spot in the bark dust under a bench. He would chase away male birds. But if a female bird approached, he would strut, cooing, and fluffing his feathers. The two would fly a circle, singing. Shortly, 4 eggs would be in that shallow dirt bowl. Every nest that I found had 4 eggs, and except for one, every egg hatched.
Baby killdeer can hunt bugs on their own the same day they hatch, although they are shaky, and cute, staggering on their spindly gams for the first hours.
Both parents initially round up the young killdeer when anyone approaches, pulling the broken wing trick, or sheltering all the fledglings beneath the adults’ wings. But the young swiftly learn to hide in long grasses.
But each day, I would see fewer birds in each family. At first there were 2 adults and 4 babies for a total of 6, then a few days later 5, then 4, and so on.
Out of ten nesting spots, the killdeer chose to nest under the benches seven times. The killdeer used at least three of those bench sites twice during the season, even though the bench nests had hundreds of people traipsing nearby daily. One nest was just outside the golf course grounds, on an adjacent road shoulder. Here's a nest in mulch at the clubhouse flower garden:
I calculated that 9 killdeer pairs hatched 48 killdeer eggs from ten locations for a total of 64 birds. I may have overestimated the numbers of adult pairs, they are marked so similarly.
On June 21, 2008, I saw the most birds, a total of 23. Twelve eggs had hatched by then, and another 12 were pending. I never saw that many again, even though about another 24 eggs eventually hatched.
After 2008, I stopped keeping close counts of the killdeer, since they apparently thrived. But in the Spring of 2010, I found a half-dozen handfuls of killdeer feathers, possibly indicating hawk predation of adult killdeer.
The killdeer adapted by abandoning their nesting sites in the bark dust under the benches, and began utilizing hardpan dried clay, under trees without concealing low limbs. They did continue to nest in the bark dust near the clubhouse’s flower garden.
This Spring, predators, probably hawks, again almost wiped out the adult killdeer. I could initially verify only two mated couples. The remaining killdeer seemed to adapt by abandoning their courting process and mating immediately, by hatching two, rather than one batch of eggs, and also by flocking for protection. However not all eggs hatched in the second nestings.
Here's a second nesting in hardpan. Something preyed on this egg and broke it.
There are now about twelve killdeer on the course. Some killdeer from the neighboring fields of row crops, and vineyards, may have relocated to the course.
I was initially concerned about finding deformed young killdeer or several failed nests, due to herbicide and pesticide usage. I found no indications of those impacts. The vast majority of nests always hatched all four eggs, although there were two partial nest failures this year, both among the attempted second hatchings, and predators may have been partly responsible for those also.
Instead efficient predators seem to threaten the killdeer’s viability. There are acres of foot-tall fescue grasses on the course where the killdeer could hide or nest, but the adult killdeer prefer bare, hard ground, even pavement, for roaming and bug hunting. The fescue does harbor mice that could prey on eggs also.
The killdeer killers left only a pile of feathers behind. I've read that hawks pluck their prey. I’ve noted active harrier hawks recently. Redtails and sparrow hawks also frequent the area. However I've never witnessed a harrier, or any critter, actually killing a killdeer. I believe the unknown predators act at night. Harriers don't wake up until about 7 am.
Oh no, I've said too much. I haven't said enough. At any rate, it's your turn to tell us about the goings-on in your area.
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After a hiatus of over 1 1/2 years, Meteor Blades has revived his excellent series. As MB explained, this weekly diary is a "round-up with excerpts and links... of the hard work so many Kossacks put into bringing matters of environmental concern to the community... I'll be starting out with some commentary of my own on an issue related to the environment, a word I take in its broadest meaning."
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