The Daily Bucket is a regular feature of the Backyard Science group. It is a place to note any observations you have made of the world around you. Rain, sun, wind...insects, birds, flowers...meteorites, rocks...seasonal changes...all are worthy additions to the bucket. Please let us know what is going on around you in a comment. Include, as close as is comfortable for you, where you are located. Each note is a record that we can refer to in the future as we try to understand the patterns that are quietly unwinding around us.
November 2014
Salish Sea, Pacific Northwest
With the coming of autumn, my local Killdeer (Charadrius vociferus) have returned to nearby beaches. They are actually in the county year-round, rare for shorebirds, but during the summer breeding season they nest away from shore. The beaches are a great source of food for shorebirds at all times of year but they can be hazardous, a narrow strip between the ocean and oceanfront properties. The San Juan islands are a popular summer tourist destination, and most beaches are continuously occupied by people and dogs, a dealbreaker for shorebirds. One of the pleasures of fall for me is seeing the tourists depart and the shorebirds return.
Killdeer are considered "shorebirds" (and that's where I see them) but they are more versatile than most shorebirds (or "waders"). Their range is throughout the continent, so you could see Killdeer in whatever state you live. They live
on open ground with low vegetation (or no vegetation at all), including lawns, golf courses, driveways, parking lots, and gravel-covered roofs, as well as pastures, fields, sandbars and mudflats. This species is one of the least water-associated of all shorebirds. - Cornell Ornithology
so if you haven't noticed these bright busy noisy bundles of nervous energy before, wander around your neighborhood. Or
listen for them. They are very distinctive! You might hear their "kil-dee" call before you see them.
One reason why killdeer migrate less than other shorebirds is the wide range of food they will eat.
Killdeer forage for food both during the day and also at night. They are omnivorous and opportunistically consume a wide variety of insects (including beetles, grasshoppers, flies, caterpillars, grubs, and mosquitoes), other invertebrates (including ticks, spiders, snails, and earthworms), and many types of berries and plant seeds. PSU
Nevertheless, recent population estimates consider Killdeer numbers to be declining, along with several other species. Fewer shorebird species are increasing in population. From the
Wader Study Group Bulletin, 2012:
Consistent declines, across all survey methods and time periods, are evident in populations of the Snowy Plover (Pacific Coast), Killdeer, Mountain Plover, Lesser Yellowlegs, Whimbrel (N. p. hudsonicus), Ruddy Turnstone (A. i. morinella), Red Knot (all populations), Sand- erling, Semipalmated Sandpiper (mainly Eastern population), Western Sandpiper, Pectoral Sandpiper, Purple Sandpiper, and Dunlin (C. a. arcticola). In contrast, strong evidence of population increase is available only for three species: Piping Plover, Hawaiian Stilt, and Upland Sandpiper.
The biggest problems for shorebirds are finding adequate food and habitat for migration and nesting. Since they feed and nest on the ground, shorebirds are more vulnerable to predation than songbirds. Even though our non-migrating Killdeer don't require as much food as those birds flying thousands of miles, they do face challenges nesting in human-altered habitats. Each fall I am relieved to see what appear to be new families.
They take flight explosively, with piercing complaints, when disturbed. However I've discovered they are less concerned when I approach from the sea than walking along the beach. Possibly it's because I have a lower profile, sitting, but perhaps it's because most of their predators are land-based. I'm able to drift along in my kayak and watch killdeer for a long time, doing their killdeer things.
Almost always my Killdeer on the beach are in small flocks though they disperse and coalesce as they wander down the beach...somebody is invariably on the watch. Mostly they dart along the edge of the water extracting amphipods, worms or other small invertebrates from the sand or washed up seaweed, sometimes dancing on the sand to make the critters below move.
(All photos by me. In Lightbox...click to enlarge)
more killdeer below...
If they stand still Killdeer are almost invisible, their sharp black and white bands breaking up their outline, blending in with vegetation and detritus. Even close up, if this one hadn't moved I'd have looked right past it.
They vary their shape with ease, further confusing a pattern-seeking predator. These are out in the open on a bare beach so we can see them better.
Stretched up:
Scrunched down:
Wing partly open... Killdeer are famous for dragging a wing like this, pretending to be injured to draw a predator away from its nest. Parents will guard a nest and nestlings although the young are on their own foraging from day one.
Their flock dynamics are fascinating. I haven't been able to figure out male or female or juvenile, the plumage of all being identical, so it's a real puzzle trying to interpret what's going on between them.
Three stood in a circle talking amongst themselves for quite some time. Then another individual approached the group. The three turned and walked away screeching loudly. The new one stopped, but continued to call after them. Not welcome evidently.
Besides blending into the background and safety of numbers, killdeer have other adaptations to avoid capture by predators out in the open. Their long wings give them quick take-off and maneuverability.
Killdeer eyes are large and set on the side of their head, so their range of vision is all around. This fellow is facing away but it can see me!
Do you see Killdeer where you live? Have you ever seen them nesting?
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