Investigating the Effect of Flock Size on Vigilance in the American Coot (Fulica americana) in Relationship to Habitat

Among many anti-predator behaviors, vigilance is observed in many species and plays an important role in survival. In this study, we investigated the effect of flock size on vigilance in American Coots (Fulica americana)foraging on land and water, by observing individual birds in these habitats and recording the time spent scanning (i.e., vigilance). Mean flock size was larger on land compared to water and vigilance negatively correlated with flock size. Birds in water were more vigilant compared to on land, regardless of whether they were foraging alone or in flocks. However, the effect of flock size on vigilance showed a weak linear correlation as it was possible that other factors (e.g., human habituation, food kleptoparasitism, or scramble competition) could have also played a role in shaping vigilance. These results suggest that there is a relationship between flock size and vigilance, which are related to previous researches that show a negative correlation between vigilance and flock size. KEYWORDS: Birds; American Coot; Vigilance; Scanning; Foraging; Flock Size; Habituation; Competition; Behavior

Redescription and new records of Polymorphus trochus (Van Cleave, 1945) (Polymorphida: Polymorphidae), in Mexico

Polymorphus trochus Van Cleave, 1945, is an acanthocephalan with limited distribution to the Americas and a common parasite of birds of the Rallidae family (Kinsella et al. 1973, McDonald 1988 and Amin 1992), mainly of the American coot Fulica americana Gmelin, 1789; however, despite existing records of this species, the knowledge and descriptions of its morphological characteristics are not sufficient. Therefore, the identification of this species can be confusing, particularly because it depends on the form of the proboscis of the female. Van Cleave (1945) provided a description and illustrations of this species based on 14 females and 2 males specimens collected in the intestine of F. americana from Lake Buckeye in Ohio, Lake Oneida in New York, and the Illinois River in Illinois; however, this description does not mention many traits that are taxonomically important. Years later, Nickol (1966, thesis not published) provided a description of P. trochus based on 36 mature specimens (14 females and 22 male) from Louisiana, but the author illustrated only the proboscis and included a schematic of the female. He described the shape and size of the proboscis in both sexes, provided measurements of the apical, middle and basal hooks of the proboscis armor, and measurements of the eggs. However, he did not mention the exact distribution of the hooks and spines of the trunk, the measurement of a complete row of hooks nor the shape of all the sexual organs, especially the female ones, which are important taxonomic characteristics in the polymorphids.

Geese, Ducks and Coots

Canada geese, snow geese, ducks, and American coots all have been implicated in agricultural crop and turf damage. Generally, goose, duck, and American coot damage to crops, vegetation and aircraft can be difficult to identify. Usually the damage to crops or vegetation shows signs of being clipped, torn, or stripped. Tracks, feces, or feathers found neat the damage can be used to help identify the species. Damage to aircraft is obvious if the bird is recovered, but if not, and only bird parts are recovered, a scientific analysis is required. Canada geese, snow geese, ducks, and American coots are federally protected by the Migratory Bird Treaty Act (MBTA), which stipulates that, unless permitted by regulation, it is unlawful to “pursue, hunt, take, capture, kill, possess, sell, barter, purchase, ship, export, or import any migratory birds alive or dead, or any part, nests, eggs, or products thereof.” Generally, geese, ducks, and coots can be hazed without a federal permit in order to prevent damage to agriculture crops and property with a variety of scare techniques. In most cases, live ammunition cannot be used.