Plankton (singular plankter) are a diverse group of organisms that live in the water column of large bodies of water and that cannot swim against a current. They provide a crucial source of food to many large aquatic organisms, such as fish and whales.lankton are primarily divided into broad functional (or trophic level) groups: 1  Phytoplankton (from Greek phyton, or plant), autotrophic, prokaryotic or eukaryotic algae that live near the water surface where there is sufficient light to support photosynthesis.
Tree swallows breed between May and September. They raise one brood per year. Tree swallows usually nest solitarily. However, they may nest near other tree swallows if nest cavities are close together. Tree swallows build their nests in late April or early May. Their nests are usually built in holes in dead or live trees or in hollow stumps. The female builds the nest using grasses, mosses, rootlets, and aquatic plants.
Violet-green Swallow. Tachycineta thalassina. A small swallow of the west, nesting from Alaska to central Mexico. Similar to the Tree Swallow in appearance and also in behavior, nesting in tree cavities and in birdhouses; it also will nest in rock crevices of cliffs in rugged terrain.Flocks are often seen flying high over mountain pine forests or over steep canyons. Forages in flight, catching insects in the air.imilar to the Tree Swallow in appearance and also in behavior, nesting in tree cavities and in birdhouses; it also will nest in rock crevices of cliffs in rugged terrain. Flocks are often seen flying high over mountain pine forests or over steep canyons. Forages in flight, catching insects in the air.