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.
Compare that to baby robins, which fledge when they are 14-16 days old and weigh over 50 grams! Swallows don't nest in trees. A swallow builds its nest on a barn rafter, bridge overhang, or other structure well off the ground. If a baby swallow doesn't make a strong first flight, it will crash on the ground. In order to survive this first flight, a swallow fledgling must have strong wings. That's why it starts exercising, flapping its little wings hard, by the time it's 9 days old.