Rosyfinch Ramblings
Comments are not moderated here - please visit NEW SITE FOR ROSYFINCH.COM
Categories:

Archives:
Meta:
June 2012
M T W T F S S
« May   Jul »
 123
45678910
11121314151617
18192021222324
252627282930  
06/17/12
Nighthawk distraction display
Filed under: General, Birding & Outdoors, Florida & SE US, Birding "Patches"
Posted by: Ken @ 6:51 am

During the couple of weeks that we were back at our permanent south Florida home, we were only able to walk out into the restored Everglades wetlands on three mornings. Threatening weather and clustered appointments kept us otherwise occupied. Yet these few encounters provided some surprises– a small band of deer that heretofore had never ventured so close to our home, second broods being raised in the heron rookery, including discovery of a third Green Heron nest, and our first sighting of a Gray Fox.  The latter stared out at us from the edge of the unpaved roadway. Not sure of whether I might be seeing an alley cat or a Raccoon, I got great binocular views of the fox’s large ears, dark muzzle, and white underparts fringed in red. I should have raised my camera first, as when I reached for it the fox scampered away too quickly for a photo op. And, that wasn’t all…

What started my fascination with birds? When I delve deeply into the recesses of my memory, I find no sudden epiphany. I recall looking out the back window of our second story apartment onto the flat roof of the dry cleaner’s store, where a nighthawk was sitting on its eggs. My father had discovered it and pointed it out to me. It was interesting to see that the eggs were laid directly on the roof pebbles, without any semblance of a nest. A few days later, the eggs suddenly disappeared. In their place, unbelievably well-camouflaged, were two chicks. Knowing the date we moved away, I was no older than four years. It sticks in my memory, but did it light a flame? (From my review of Avian Architecture)

Nighthawks are masters of erratic flight. Their wing beats have no regular cadence, speeding up and slowing down, dipping and diving. Seeing a choice insect, they can make a right angle turn with no warning. Getting one in the camera viewfinder is a challenge, much less than keeping it there and depressing the shutter at the right instant. My flight shots of nighthawks are usually 90% sky and clouds, with perhaps a snippet of tail-feathers or wingtips.   

Common Nighthawk 20110422

Common Nighthawk in-flight 20110419

Since nighthawks are most active at the ends of the day, I am lucky when one banks to catch the rays of sunrise on a wing surface.

Common Nighthawk 20110501

Common Nighthawk 2-20110422

Nighthawks usually land on the ground, but may perch lengthwise along a branch or even a utility line.

Common Nighthawk 3-20120614

Common Nighthawk 20110426

Common Nighthawk at sunrise 20110422

Common Nighthawk 20110421

This past week, a few days before we returned to Illinois from Florida for the second time this year, we found the nest of a Common Nighthawk. A nighthawk flew up some distance ahead of us as we walked along the edge of the gravel road that leads into our local wetlands patch. I fixed my eyes on the exact spot where it had been resting, and, standing back on the road several feet away, we methodically searched for its nest.

Nighthawk eggs and chicks blend in perfectly with the pattern of pebbles and stones, and it would be very easy to step on them if we did not place each step very carefully. I found the nesting site (it cannot be called a “nest” as it had no visible structure) next to a small tuft of grass, quite dangerously near the tracks of deer, raccoons, bicycles and joggers.

The eggs were set apart from each other, suggesting that the adult may have been shading them from the sun rather than incubating them.

Common Nighthawk eggs 20120613

The next morning the eggs were close together. Nighthawks have been known to move their eggs some distance, clearing larger stones out of their path as they rolled them. In his classic Life Histories of Familiar North American Birds, Arthur C. Bent writes:

The eggs do not necessarily remain in the position in which they are first laid, especially when the nesting site is on a comparatively level surface such as that provided by graveled roofs. During the period of incubation of two nests under daily observation, the eggs were gradually moved a distance of 5 to 6 feet. This shift in position comes about by the habit of the female pulling or pushing the eggs under her breast, thus moving them a short distance each time she settled on the eggs. As the direction of the bird’s approach was more or less constant, the eggs were moved in the same general direction. This resulted in a distinct trail being formed, giving an appearance that one would expect to see if a giant snail had traveled over the graveled surface and forced the larger pebbles to one side. B. H. Warren (1890) writes that the eggs of a nighthawk in one instance were moved 200 feet by the bird, which carried them in her mouth. I have never been able to verify this extraordinary behavior of a nighthawk transporting an object as large as an egg in its mouth. (http://birdsbybent.netfirms.com/ch11-20/nighthawk.html)

Common Nighthawk eggs macro SOOC 20120614

We retreated as the parent bird returned to shelter the eggs, and photographed her (or him, as both sexes take part in incubation) on the nest site.

Common Nighthawk on eggs 20120614

The next morning, Mary Lou was ahead of me as we walked along the gravel road. Suddenly she was startled when a nighthawk flew up right in front of her. It actually flew towards her, then fell to the ground, flopping and rolling as if in agony. It was obviously performing a distraction display, and the amount of energy that went into it suggested that Mary Lou had nearly stepped on the eggs (or more likely young birds). I had to set the camera on macro to get these shots, as the bird allowed a very close approach before moving away. We briefly examined the area from a safe distance but did not see any eggs or young– not surprising, as they are well camouflaged.

Common Nighthawk 20120614

Common Nighthawk macro SOOC 20120614

The bird was obviously under great stress, so we did not remain there very long. As we walked away it resumed a more normal posture and flew back to the nesting area. In the meantime, its mate had been flying back and forth on the opposite side of the road, issuing soft calls that sounded like “kwoo,” quite unlike the familiar loud and shrill “peent” that we often hear from flying nighthawks.

Common Nighthawk 2-20120614

17 comments