Many of these birds arrive at month's end. Landbirds come through in big numbers in April, although those species that winter in the tropics do not peak until May. In the open areas, swallows will make their presence known and more will arrive at the end of the month. Some of these are Neotropical migrants. These species will commence nesting activities in mid-late April, although the fickle weather can turn the birds off making them difficult to see and hear.
Hawks come through in good numbers and can be seen practically anywhere.
There are no real aggregation locations, although more will be seen near the tip of the peninsula as they hunt the fields and forest edges. April is a turning point month. The wintering birds are still around in decent numbers while the first of the Neotropical migrants are returning. The day to day changes in birdlife are the most exciting part of spring migration and April offers a grab bag with new species arriving almost daily. The New York City Audubon Society Guide to Finding Birds in the Metropolitan Area with Marsha Fowle.