Nature Ramble at the End of July

As I make my way through the fields and forests in late July, I can feel a definite change in the air. It is much hotter and more humid of course, and many plants have fruit on which the birds are feeding. The most obvious signs of the season are the maturation of the summer grasses, the appearance of fruit on trees (magnolias especially are obvious), the drop in bird song as the breeding season of many species comes to an end, and a change in frog calls to the summer breeding species.

As I walked along a woods trail I noticed a loud humming noise from a hovering insect which at first I thought was a yellow jacket wasp, but turned out to be this fly mimicking a wasp. There are a remarkable number of these wasp mimics, many of which are flower or syrphid flies. I never cease to be amazed by the resemblance between the harmless fly and the dangerous wasp. Indeed just recently one of my grandsons was stung by yellow jackets and chased more than 400 yards when he disturbed a nest. Obviously bird predators remember such encounters well and avoid these mimics.

A more benign meeting with an insect was a close encounter with a red admiral butterfly which was hanging around our back porch. It landed on my hand and proceeded to suck up the sweat with its proboscis. This is a form of “puddling” behavior which is more often observed when butterflies land on damp salty substrates (mud, mammal dung, animal carcasses, etc.) and imbibe the fluids. This is a means by which these herbivores can obtain salts, especially sodium. Of course humans also require sodium as a major constituent of our blood but find it easier to supply this need by eating meat.

This time of year the summer-breeding frogs, bullfrogs and green frogs, are quite evident by their distinctive calls. The green frog seen here sunning on the bank can be recognized by its “rubber-band call” and by the characteristic lateral fold that extends down the edge of the body. The bullfrog lacks this fold. But the two frogs are similar in that the males have a very large eardrum to aid in recognition of the territorial calls given by the males.

If you are walking near a creek or pond you will certainly notice the results of turtle nests being robbed by various predators (raccoons, foxes, armadillos, coyotes, etc.). Female turtles generally seek out locations of open ground and dig a small hole with their back feet to deposit their eggs. These nests are often robbed by predators which must smell them. It seems remarkable that any turtles survive, but the very long life of the adults must compensate for the large egg mortality.

I check our bird nest boxes periodically to see how things are progressing. I was excited to see what is likely a third clutch of bluebird eggs just in the process of hatching on July 27 (see photo). Bluebirds are beautiful, grace our home surroundings with their presence, and breed persistently. Since cavity nesting birds are limited by the number of suitable holes, there can be considerable competition for cavities, including the boxes humans set out. Tree swallows seem to win out over bluebirds for boxes placed in open areas, but only have one brood in some areas. Bluebirds continue to nest and encounter some minor interference from house wrens. I have rarely found that house wrens can dominate bluebirds but this nest box shows how a first season bluebird nest was over-topped by sticks placed by a house wren. These sticks were not likely a nest but simply a means of discouraging nesting by any competitors.

So enjoy the dog days of summer while they last and observe the natural progression of the patterns of summer and its wonderful critters.

Bill Dunson, Englewood, FL & Galax, VA
wdunson@comcast.net