Activity Budgets, Foraging Behavior, and Diet of White-Tailed Kites (Elanus leucurus) During Breeding and Nonbreeding Seasons In the Argentine Pampas

Abstract

From 2005 to 2009 we evaluated the activity patterns and food habits of White-tailed Kites (Elanus leucurus) during the breeding and nonbreeding seasons in the Argentine Pampas. According to time-activity budget analyses, perching was the most frequently observed activity during the nonbreeding season (52% of total time), whereas foraging was the most frequent activity during the breeding season (41% of total time). Flight was the least frequent of all kites' activities in both seasons (8% and 9% during the breeding and nonbreeding season, respectively). Even when kites spent a similar percentage of time foraging during both breeding and nonbreeding seasons (41% and 39%, respectively), their hunting technique differed between seasons. During the nonbreeding season, we only observed kites using active searching to forage, but during the breeding season, we observed them using active and passive searching in similar proportions. According to pellet analyses, the diet of kites was mostly composed of rodents (. 96% of total prey). Small rodents (body mass , 35 g) were dominant in numeric terms in the diet in both seasons, but larger rodents represented the bulk of biomass. Our results indicate that in the Argentine Pampas, White-tailed Kites are predominantly mammal-eating, active-search predators, as previously reported for the species in South America and North America and for other Elanus species around the world.

Reproductive behavior of White-tailed Kites (Elanus leucurus) in the Pampas of Argentina

“…Studies on raptor behavior are scarce in the literature, especially in the Neotropical region. In the case of the White-tailed Kite, there is an asymmetry between the information available for North and South America (Hawbecker 1940, Watson 1940, Warner & Rudd 1975, Mendelsohn & Jaksic 1989, Baladrón et al 2018. Although based on sporadic records and a modest time of observation, our study show that in the Pampas the White-tailed Kite have a prolonged breeding season and show a pronounced division of roles in parental care between sexes.…”

“…Most studies performed along the species' distribution range agree that this kite is a specialist predator of small mammals, particularly rodents (USA: Hawbecker 1940, Bond 1942, Dixon et al 1957, Waian & Stendell 1970, Stendell & Myers 1973Chile: Meserve 1977, Schlatter et al 1980, González-Acuña et al 2009Argentina: Leveau et al 2002, Sarasola et al 2007, 2010, Baladrón et al 2018Brazil: Scheibler 2004). This species is characterized as an active-search predator that uses hovering as its main hunting technique (Watson 1940, Warner & Rudd 1975 Reproductive behavior of White-tailed Kites (Elanus leucurus) in the Pampas of Argentina Jaksic 1989, Dunk 1995, Baladrón et al 2018. The information available about reproductive behavior of the White-tailed Kite is scarce and mostly comes from North America (e.g., Hawbecker 1940, Watson 1940.…”

“…In the framework of a broader study on foraging ecology of the White-tailed Kite in the Pampas of Argentina (see Baladrón et al 2018), we registered different activities of kites related to reproductive behavior. In this study, we compiled and analyzed the information collected during such sampling, emphasizing on reproductive phenology, parental care, and prey transfer activity.…”