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.
1 TREE SWALLOW: The Tree Swallow is a common swallow of marshes and open fields. 2  It is an inhabitant of nest boxes. 3  The Tree Swallow winters farther north than any other American swallow, and it returns to its nesting grounds long before other swallows come back. Cliff Swallow chicks only get to leave the nest once, no going back. 2  They have to wait until the time is right. 3  An unmated male Barn Swallow may kill the nestlings of a nesting pair. 4  His actions often succeed in breaking up the pair and afford him the opportunity to mate with the female.