Snail Kite

Rostrhamus sociabilis

The Snail Kite is a bird that relies on wetlands to forage for their main prey item: snails. This makes their migratory patterns especially interesting to Smithsonian scientists, who are tracking this species in South America.


Height: 39–48 cm; wingspan 99–115 cm (Bierregaard and Kirwan 2017)

Weight: male 304–385 g; female 384–413 g

Conservation Status: Least concern; Snail Kites are sexually dimorphic: males are slate colored with a white rump, whereas females are brownish, steaked dark, with a white rump.


Although the Snail Kite is listed as “least concern” by the International Union for Conservation of Nature (IUCN), there is surprisingly little known about the South American population. As the name suggests, this species of kite feeds almost exclusively on snails, therefore inhabiting wetlands throughout most of the year. By tagging Snail Kites in Brazil, Smithsonian scientists and their Brazilian colleagues hope to answer questions such as: When and how fast do they migrate? Where do they spend the non-breeding season? What is the relationship between water quality/levels, snails and movements of a specialist snail feeder? In addition, there is a relatively well-studied population of Snail Kites that is found in Florida that can provide a point of comparison to the lesser-studied South American population.

Snail Kites that breed in southern Brazil may migrate north after the breeding season, spending the non-breeding season in the Pantanal (Antas 1994), one of the largest wetlands in the world. To describe these movement patterns, scientists are studying Snail Kites at Taim Ecological Station in southern Brazil. This protected area primarily consists of wetlands that host a large variety of plant and wildlife species. Verbail traps are used to capture the Snail Kites, which consists of an artificial perch on top of a monofilament noose attached to a spring. When a Snail Kite lands on the perch, it releases the spring, closing the noose around the kite's feet. The kite is quickly removed from the trap, measured, and tagged with a satellite transmitter before being released. These satellite transmitters send us the position of each kite every two days for several years. One of the kites visited four countries (Brazil, Uruguay, Argentina, and Paraguay) in the first two weeks after being tagged, giving us new insights into the high mobility of these birds. Smithsonian scientists are excited about the potential for these tags to provide interesting data about the movements of Snail Kites and other poorly understood migratory birds in South America.

Meet the Team

Pete Marra, Ph.D.

Director, Georgetown Environment Initiative
Laudato Si' Professor of Biology and the Environment
Georgetown University
Emeritus Senior Scientist, Migratory Bird Center
Smithsonian Conservation Biology Institute
National Zoological Park

Brandt Ryder, Ph.D.

Research Scientist
Smithsonian Conservation Biology Institute Migratory Bird Center
National Zoological Park

Alex Jahn, Ph.D.

Migration Patterns Fellow
Indiana University
Environmental Resilience Institute

Evan Buechley, Ph.D.

Post-Doctoral Research Fellow
Smithsonian Conservation Biology Institute
Migratory Bird Center
National Zoological Park


Scholarly Articles

Antas, P.D.T.Z., 1994. Migration and other movements among the lower Paraná River valley wetlands, Argentina, and the south Brazil/Pantanal wetlands. Bird Conservation International, 4(2-3), pp.181-190.

Bierregaard, R.O., Jr & Kirwan, G.M. (2017). Snail Kite (Rostrhamus sociabilis). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from on 16 December 2017).

Jahn, A. E., Levey, D. J., & Smith, K. G. (2004). Reflections across Hemispheres : A System-Wide Approach to New World Bird Migration Author ( s ): Alex E . Jahn , Douglas J . Levey and Kimberly G . Smith Published by : American Ornithological Society Stable URL : REFE, 121(4), 1005–1013.

Sykes, Jr., P. W., J. A. Rodgers, Jr. and R. E. Bennetts. 1995. Snail Kite (Rostrhamus sociabilis), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America Online: