Wednesday, August 17, 2016

A Killdeer Family, Kempton, Pennsylvania


On a rocky patch of ground, ever at the mercy of the elements, a Killdeer sits silently waiting. Every so often it rises, exposing a divot barely discernible and four tapered eggs that are similar in volume to a medium-sized hickory nut. The bird carefully examines them, rearranging if needed, leaving the tapered end always towards the center in meticulous symmetry. If the day is cool or wet, it returns to its seated position. If it is hot, the Killdeer lets the sun’s rays do the incubating while standing nearby. Overall, the eggs are a creamy tan with chocolate splashes and speckles. The colors are specially designed to work in unison, camouflaging the precious packages against the rocks. They are all but invisible to those who are unknowing of this particular game, played yearly by nature. The only tip to the nest’s whereabouts comes from the adults’ behavior when approached. Both parents look after the nest, usually one at a time, and attempt to lead away intruders with a feigning technique. Pretending to be injured, the bird flops away, tail fanned to expose rust-colored feathers and rump that vary abruptly from the other browns found on its plumage. The Killdeer also spreads a wing during the display, baring black-and-white flight feathers. This is a sure sign of a nest nearby.

Adult on nest. 

The Eggs.
After almost exactly two weeks of this, sometime during the night of July 4th, the eggs hatched beneath the booming of Independence Day fireworks. The newly hatched young, all four successful, can walk as soon as their down dries, but never stray more than a few feet from their parent and are usually out of sight. With young nestled underwing and among soft breast feathers, the adult looks like it has extra legs.


As typical of shorebird babies, the young Killdeer are lanky. No taller than their parent’s belly, they are little more than balls of down on stilts. The young are subtly beautiful; their plumage utilitarian to keep them safe from predators. Their brown is darker and more mottled than the adults, who are more ruddy. Black outlining marks the boundary between browns above and white below; a black collar encircles their tiny throats. The young roam, run, and pause to flick their bodies up and down, a typical Killdeer behavior. A helpless hors d’oeuvre for many predators, there will be no time in their life more vulnerable than this.


After a few days, the young begin a strict routine as they can stand to spend little time away from the warmth of a parent. By July 6th, they still never stray far from home, staying in the small rocky patch, but are getting braver with each passing day. By 6:00am, the family is already on the move with the adult-on-duty calling constantly. Over the last few days, they have become accustomed to my morning presence and allow me to get close, but not too close. I sit in the gravel patch and observe, silently taking photos. When the chicks leave their parent’s side, it periodically gives a single-note dee to keep in contact. The young explore the gravel and nearby short grass for about eight minutes, looking for food. Shorebird chicks are precocial, meaning they are not fed by a parent in the manner typical of many birds. Once standing, they can mostly care for themselves. After the few minutes of adventure, the adult emits a quick dee-dee. Sometimes all at once, sometimes one-by-one, the chicks come running, gliding across the rocks on long legs. Occasionally, a defiant individual doesn’t listen, much like humans and much to the chagrin of their parent. The adult is only ever harsh when a chick ventures too far or doesn’t listen to the round-up call. This prompts a more assertive version of the routinely patient “dee”. One at a time, the young disappear into the adult’s downy breast feathers. It adjusts itself until all are invisible, save for long legs. The chicks could be getting a few moments of shut-eye, but this is mostly to keep them warm. At less than a third of their adult size, they cannot properly thermoregulate with only a sparse layer of down feathers. Five minutes later, the adult gives the same two-note call it used to round the chicks up and, one-by-one, the warmed killdeerlets disperse. The routine begins again. 

One little one out, the rest are beneath the adult.
July 9th marked the first day the adults let their young stray further than about six meters from home. Over the next week, they will wander around, exploring their two-times expanded world, now spending more time in short grass than gravel. This is probably due to increasing daytime temperature, food availability, or a combination of the two. The chicks love their freedom and are innately curious. They pick at everything in sight, pulling at weeds, lifting chips of wood, and flipping pebbles. 

But life isn’t always blue skies and wildflowers when you’re a bite-sized morsel. Approaching danger causes a quick, loud volley of dees from the adult. At this, the chicks hunker down into the rocks or grass, disappearing from sight. This has been caused most often by a pair of American Kestrels nesting nearby, whose young, I’m sure, would love a tasty killdeerlet. Life continues to be very dangerous, as the parents have loosened their reins. Sometimes during one of these scares, the adult disappears. I suspect this is not only to lead a would-be predator away from the young, but also because the tending adult is a danger to its young by being near them and more visible.

Sometime around July 11th, the daytime incubation stopped, so there was no need for them to stay as close to an adult. Though an adult still accompanies the chicks in their wanderings, their range is now very large. Occasionally, the adult killdeer jumps into flight and circles over the young, calling, before landing at another location up to 20 meters away. Could the circling behavior also be a flight demonstration? Sometimes, this is when the adults switch shifts, other times, the same adult remains with the young. The parent gives a normal series of dees from the new location, slowly calling the young towards it. Close observation on the same day shows the chicks are quickly growing wing coverts and a few days later, they are completely formed. Despite the lack of most adult feathers, the young killdeer are beginning to look less like bolls of cotton on stilts and more like the finished product.


By July 17th, the killdeerlets measure up to nearly ¾ the size of their parent. They are never stationary, ever on the move, and run circles around the adult; often wandering far. Around the same time incubation stopped, the young found their voices. At first their noises were soft, but still vaguely killdeer. By July 20th, the four young had found their voices at nearly full volume. They give a calm dee, like the adults. Usually this seems to be random baby talk, but occasionally, the tending adult gives the “predator!” dees, to which the young respond once danger has passed.

As the birds grow, life becomes less dangerous. Nearly full grown, but not fully feathered, the young are able to escape danger via their own close observation and that of their tending adult. They are also becoming too large and fast for local, open-country predators. The birds have grown very quickly and flight feathers are beginning to peek out of protective shafts. The four killdeerlets are also showing the tell-tale reddish eye rings and the second of two black collars, distinct in their species. One individual is slightly smaller than its siblings, but it keeps up well and seems not to have been too slow in catching on at the game life.


The morning of July 21st was uncharacteristically cold for summer, even for Pennsylvania. The thermometer read 58°F, forming fog, and leaving a chill in the air all morning. A cold dew lay upon earth causing purple coneflowers and yellow sunflowers to appear richly bejeweled. Though the sun should have been up an hour earlier, fog continued to block its warm rays. Wondering how such a morning would effect my new friends, I decided to search for them. They had already been found by another biologist, who relayed the story I was looking for. The adult was seen lying down with wings spread over the grass. Beneath its warm embrace were the four young, two under each wing, too large for brooding among the feathers of the adult’s breast. Though the killdeerlets had not needed brooding for ten days, the temperature made today an exception. I am constantly amazed at how the creatures of nature can quickly adapt to temporary extremes in their respective environments.


An update on July 27th provided information that all four young still survive. This is an amazing feat when you consider their several weeks living as the perfect size for a predator; not to mention this family lived in close proximity to a busy highway, constantly close to dangerous vehicles. Though they have passed through the most hazardous part of growing up, the four siblings will probably not all survive their first year. Whether they will die at the hands of disease, humans, or a lucky predator, remains to be seen. This is the brutal truth of the natural world and why small to medium-sized birds (and other animals) have multiple young. It is now hard-wired into the DNA of Killdeer that an average of four is the perfect number of eggs to ensure at least one survives to carry on the species. On a lighter note, on July 27th the killdeerlets continue to grow and now have flight feathers that are almost completely formed. With a little muscle-strengthening as they try out their new tools, they will be airborne in no time at all. By July 29th, they had all “flown the coop”, to be cliché; or at least dispersed from the immediate area.

One of the nest's adults and what the surviving young will grow up to look like. 
Killdeer are widespread throughout both urban and rural North America and have adapted well to living in human-altered environments. Observing the nesting of a bird and the raising of its young is a great way to immerse yourself in nature. It’s so easy to get distracted in this world, but there is something about watching an ancient process that helps draw us back to reality. Birds are all around us all the time. They will always remain a way to stay connected to what really matters.

For more photos in this sequence, visit: http://www.pbase.com/mpruitt/killdeer_family
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