As Summer progresses you may expect to see different natural events that change with the seasons. Birds sing less after many of them complete reproduction, some reptiles reproduce, there are changes in flowering (phenology) and some butterflies and dragonflies emerge that were not present or were very rare earlier.
One bird that is common but not often seen is the scarlet tanager, in this instance the brilliant male. It is extraordinary that such a brightly colored bird is rarely seen, but it is found mainly in dense tree foliage and does not move around much. This male attracted my attention by chance when it was sitting on a branch of white pine. This is a classic example of the “pretty male” phenomenon in which the females appear to choose their mates by bright colors, which likely indicate a healthy male. Strangely enough the red feathers are molted in winter whereas the summer tanager remains red all year.
Some birds that might be considered “trash birds” in other locations are unusual in Watauga County, NC, and thus desirable for a county list. I see immature black crowned night herons and great egrets daily in FL but very much enjoyed watching them in the mountains of NC. “Location, location, location” is not just a factor in choosing real estate! On the other hand the nest of a very common bird the song sparrow is rarely seen. This nest with marvelously camouflaged eggs was found in a shrub just at our front door. The ability of this species to adapt to human surroundings bodes well for its future.
One common reptile that is not often welcomed into our houses is this black rat snake which I found in our basement. It turned out to be a female and several days later laid 17 oblong eggs. In about 60 days these will hatch into juveniles that are blotched not black; the color difference is likely related to camouflage effects that differ with age. Although this snake is named a rat snake, it often eats birds instead, possibly depending on the most common prey available to it. I tested the food preference of this female which was hungry after egg laying and she quickly ate two mice.
I was vey happy to suddenly see numbers of pipevine swallowtails which had been very uncommon prior to late July. The caterpillars of these striking butterflies feed only on poisonous pipevines which are not commonly observed in our area. They are famous for being toxic due to their larval food and warning birds not to eat them by their bright coloration. A number of other butterflies gain protection from this warning coloration by being mimics- a chief example being the black tiger swallowtail (females only) shown here. Other mimics are the red spotted purple, the spicebush and black swallowtails and the female Diana fritillary. You will be confused by these “black and blue” butterflies until you gain some experience identifying them.
One of the most conspicuous and common beetles in late summer that are found feeding on dog bane plants (closely related to milkweeds) in old fields and disturbed forest edges is the dogbane beetle, here shown as a mating pair. Note that the male and female are identical but very brightly marked in iridescent colors. These are structural colors based on light refraction and vary according to the angle of observation. Such bright colors warn predators that they are toxic.
A large dark fishing spider that I found on our house siding was carrying an egg sac to protect it from predators. It is interesting that such relatively primitive animals have a strong maternal instinct and even forgo feeding to protect their young. But this behavior that we humans might consider an advanced trait in fact appears very early in the evolutionary tree. Observation of a male widow skimmer dragonfly leads one to a similar conclusion- it is brightly colored whereas the female is drab. It protects a breeding territory along a pond and courts and mates with females that choose it for its external characteristics. A primitive insect example of the “pretty male” behavior showing how far back this goes.
There is much of interest in the natural events of Summer although they can be very different from Spring. Very soon we will witness the large scale migration of birds and insects to the south to escape the oncoming winter. I expect nighthawks to be flying over our house in hundreds very soon and am looking forward to observing this annual phenomenon.