Comparison of the avian biodiversity between the state of Rio de Janeiro and Fairfield County Michael L. DeLea SUMMARY: Our results show that in seven hours of surveying bird species in the state of Rio de Janeiro, we identified representatives of 24 bird families and 54 bird species in total. This is compared with the 39 families and 93 species documented over a four year period in Fairfield county. There are 17 families that have representatives in both areas, including some species that are present in both locations, and seven families whose members were only found in Brazil (See fig. 2 and fig. 3). Including the native and migratory species, Brazil ranks third world-wide for the greatest number of bird species with an astounding 1,677 specimens and the state of Rio de Janeiro accounts for 732 of those species. This is compared to the 888 species of the United States (ranked 23rd) and the 424 recorded species of Connecticut. Our results give evidence to the argument that Brazil has greater avian biodiversity because the majority of families present are represented by at least two species while this is not the case in the data from Farifield County. This can be correlated to the existence of a diversity of ecosystems that provide niches for the avian populations. Unfortunately, the threat of extinction continues to be a concern due to alteration of habitats, increased resource demand, and other human activities. Currently, there are over one hundred indigenous bird species that are on the endangered list and face extinction if conservative action is not taken. INTRODUCTION: South America is among the most biologically diverse locations in the world, and Brazil is no exception. Being home to several different ecosystems (see fig. 1), including the Atlantic Rainforest and the endangered Brazilian restinga, it is easy to understand why such a large number of species inhabit the region. Brazil boasts a great diversity of mammals and plants, but the avian biodiversity in particular accounts for about one sixth of the population. Our goal was to collect data on the largest number of avian species possible and compare the information with species numbers representative of Farifield county. METHODS: Brazilian bird species were documented during a seven hour period in a variety of habitats including restinga, wetlands, and mangrove forest. Birds were observed and identified in their natural habitats by morphological features such as color, approximate size, beak form, behavior, etc. At times, bird call playback was utilized to lure out concealed inhabitants. The biodiversity data from Fairfield county was collected over a four year period by Fairfield University’s ornithology class that sampled various local habitats. Special thanks to Dr. Brian Walker, Dr. Ashley Byun-McKay, Dr. Tod Osier, Salvatore Siciliano, Luciano Moreira Lima, Bruno Carlos Rennó Ribeiro Soares, and Helio Kinast Cruz Secco without whom, this project would not have been possible. Department of Biology Fairfield, CT Figure 2. From the family Threskiornithidea, the Roseate Spoonbill (Platalea ajaja) Figure 2. From the family Thamnophilidae, the endangered restinga antwren (Formicivora littoralis) Accipitridae (Hawks and eagles) Anatidae (Ducks, geese and swans) Ardeidae (Herons and bitterns) Cathartidae (New World vultures and condors) Cerylidae (Water Kingfishers) Charadriidae (Plovers and lapwings) Columbidae (Pigeons and doves) Falconidae (Falcons and caracaras) Hirundinidae (Swallows and martins) Icteridae (New World blackbirds) Laridae (Gulls and terns) Mimidae (Mockingbirds and thrashers) Passeridae (Old World sparrows) Psittacidae (Parrots) Scolopacidae (Sandpipers) Strigidae (Typical owls) Tyrannidae (Tyrant flycatchers) Rio de JaneiroFairfield County Number of families2439 Number of species5493 Table 1: Family and species occurrences in the state of Rio de Janeiro and Fairfield County. Great Blue Heron White-browed Blackbird Orchard Oriole Monk Parakeet Orange-winged Amazon Eastern Phoebe Masked Water-tyrant Lesser Yellowlegs Merlin Crested Caracara Roadside Hawk Red-tailed Hawk Avian families with representatives in both Rio de Janeiro and Fairfield County Figure 1. Six different biomes characteristic of Brazil. These include the Amazon Rainforest, “Caatinga” or dry forest region, Cerrado or tropical savanna, Pantanal or watershed, Atlantic Rainforest, and the Pampa grasslands.