Reports from around the region suggest a distressing number of vacancies in bluebird nesting boxes.
Some say that where bluebird activity is usually brisk, now they are seeing little or none.
Bluebirds that might have filled some empty boxes seemingly were dead and gone before the current nesting cycle got off the ground.
Accounts from across the region suggest an alarming number of eastern bluebirds â “ hundreds or thousands over a wide area â “ died in late winter and early spring. A common observation is that dead birds were found in nesting boxes.
The timing of the sad discoveries makes sense. In late winter, lots of bluebirds were in the area, some local nesting birds perhaps on the verge of rituals for the new nesting season, others likely birds from northern territories that had not yet migrated back up the flyway.
About the time that winter weather typically moderates here, sharp cold dug in and lingered. Late winter also brought repeated dosages of snow, sleet and even a touch or two of freezing rain.
Severe cold seems to have sapped bluebird energy reserves while snow and icy crust locked up food sources. Stressed by energy demand and sharply limited on the supply side, bluebirds ran into an unusually harsh incidence of winter mortality. Many died of too much cold, too little food.
Birding authorities say cavity-seeking bluebirds in winter weather are drawn to the same man-made boxes where they nest in spring. In cold, bluebirds gravitate to the boxes for thermal shelter and a break from wind and precipitation. Several birds may gather in each box.
Concentration of sheltering birds also concentrates signs of loss. Ornithologists say winter kill in a box packed with birds can make it look like a death chamber. A couple of reports have indicated as many as 14 bluebirds found dead at single boxes this year.
Authorities say it's common to find a few dead bluebirds, winter mortality victims, in nest boxes. But the numbers found hereabouts sound harsh.
Bob Peak, a Henderson bluebird volunteer who tends and monitors bluebird trails in the Land Between the Lakes and at Lake Barkley State Resort Park, reported finding 68 dead bluebirds among 230 nest boxes there. He reported that the average find of dead birds in early spring is four or five.
Among 170 boxes maintained in the LBL, late April monitoring found only about 45 percent of them occupied by nesting bluebird pairs as compared to a normal rate of 75-85 percent.
Dr. Wayne Davis, former University of Kentucky biology professor and director of the Kentucky Bluebird Society, said, while winter of 2013-14 may have been the worst in years for bluebird, some winter mortality is routine.
He said several birds sheltering in the same nest box is normal behavior. Davis noted that bluebirds dying in those communal box roosts is the product of winter conditions, not overcrowding.
Davis said human supporters of bluebirds need not do anything different than standard practices to provide for the birds in the aftermath of the apparent sizable winter kill here.
"You can think about providing food for them next winter," Davis added.
Otherwise, keep nesting boxes out there all year and maintained, allowing the surviving bluebirds to carry on.
"They'll come back in a couple of years," Davis said.
n Some birds that are alive and well would have you think they're in great distress.
Those brown and white birds that are sometimes seen running around and acting strange on bare fields, parking lots, athletic fields and mudflats are killdeers â “ a species named for its shrill call, not something it does to larger mammals.
Killdeers are a type of plover, actually a kind of shorebird that is the least associated with water bodies and actual shores of all its kin. It's a bird 8-11 inches long with an 18-inch wingspan. Lanky, with relatively long legs and beak, the killdeer is mottled brown on upper body with white below, plus it has one or two black neck bands.
It's a ground-nesting species, the nest of which amounts to little â “ a sort of a palm-sized, scuffed depression in dirt, sand or rocks. A killdeer's speckled eggs are naturally camouflaged, especially among small rocks or gravel.
A killdeer doesn't guard its nest, so to speak, but if you walk across a gravel lot toward its nest, the parent bird will make a fuss while splaying its tail and cocking one wing out at an odd angle â “ the infamous broken wing ploy.
The killdeer vigorously puts on a show of being injured and in great distress as it runs from the nest, a bid to draw predators away from its defenseless eggs or chicks on the ground. But chase after one closely and it ably will fly away with no sign of disability. (Golly, I'm all better now.)
Many people have seen this show of dramatics from a killdeer without knowing that the bird was perfectly fit â “ and without knowing that they seemed to be predators.
Steve Vantreese, a freelance outdoors writer, can be contacted at firstname.lastname@example.org.
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