“Case Studies in Land-use, Bird and Plant Dynamics” is a course in the Environmental Science Department that looks at plants and birds as monitors of environmental change. Several trips are scheduled to survey nature in the heart of NY City and in nearby suburban and rural areas. The three core topics are bird migration, paleo-environmental reconstructions, environmental transformations.
Taught by lecturer Terryanne Maenza-Gmelch, the class has been conducting bird population surveys this semester at Jamaica Bay, Central Park, Black Rock Forest and Sterling Forest. One area of interest was to monitor the arrivals of neotropical songbirds, which typically occur over several weeks during late April and May. These birds spend the winter in the tropics and fly back to North America in the spring to breed.
The last field assignment of the semester was as follows: Go to the 86th-floor observation deck of the Empire State Building on an evening in April. Select an evening as late in April as possible, one close to the full moon, with a wind from the south or southwest. Be sure it is an evening with good visibility and pick a night when the building's lighting schedule calls for "white" lighting. Arrive just after sunset. Migration will start about one hour after sunset. Purpose: to document and count night-flying migratory songbirds as they head to their northern breeding grounds after spending the winter in the tropics.
April 30, 2010 was just such an evening. Dr. Maenza-Gmelch and her 9 students assembled 1050 feet above street level and waited, looking up. At 8:45 PM. the first birds flew over, 200 in the first 15 minutes. The pace picked up. Heading north and passing just over the peak of the building at 1472 feet, another 261 birds were counted in a 15-minute period. Students estimated that 800 to 1000 northbound migratory birds fly over the building per hour at night when conditions are right. The birds cannot be identified under these conditions. However, during a trip to Sterling Forest (40 miles north of the Empire State Building) two days later, the class found numerous newly arrived migrant birds like wood thrush, prairie warbler, scarlet tanager and great-crested flycatcher. These species could possibly have been among the flocks that were flying over the Empire State Building.