Poplar (also called Aspen) buds are an important winter food source for wildlife, but for none as much as the Ruffed Grouse. During the course of a year, a Ruffed Grouse may feed from as many as 100 species of plants, but in the winter, species of poplar are by far its most important food source. In fact, the relationship between grouse and poplars is such that the range of the Ruffed Grouse is practically identical to the range of Trembling (also known as Quaking) Aspen (Populus tremuloides) and Big-tooth Aspen (Populus grandidentata).
Poplars are dioecious – the male and female flowers grow on separate trees. Although grouse will settle for any poplar bud, it is the male flower buds of Trembling Aspen trees which they prefer, due to the buds’ high amounts of proteins, fats and minerals. (Female buds are smaller and have less nutrients, oddly enough.) Ruffed Grouse seldom feed on a poplar tree that is less than 30 years old. Perhaps these older trees have more vigorous buds, or perhaps their branches are easier to perch on because they are larger. (Information source: Ruffed Grouse: Woodland Drummer by Michael Furtman)
A leaf miner is the larval stage of an insect (primarily moths, sawflies and flies) that feeds on leaf plant tissue. Most of these insects feed for their entire larval period within the leaf, creating tunnels between the upper and lower leaf surfaces. Some will pupate within the leaf mine, while others cut their way out when they are full-grown and pupate in the soil.
The pattern of feeding tunnels, as well as the pattern of droppings, or frass, within them (darker sections of tunnels), combined with the species of plant on which they occur, can sometimes identify the species of insect that created the mines. A moth larva, the Common Aspen Leaf Miner (Phyllocnistis populiella), leaves delicate, serpentine mines (see photo) that are diagnostic of this species.
The flower buds of Trembling Aspen (Populus tremuloides) look a lot like pussy willows when they first open up and the tip of the catkins (flower spikes) emerge. Long before the leaf buds open, the flower buds swell and their scales open to reveal male and female flowers that mature into pendulous catkins (male and female catkins are on separate trees). In a month or so, after pollination, the seeds that have developed on the female catkins will be dispersed by the wind and the air will be filled with cottony fluff. (photo: male Trembling Aspen catkins)