Southernmost record of Yellow-headed Vulture , Cathartes burrovianus Cassin , 1845 ( Cathartiformes , Cathartidae ) , in Buenos Aires province , Argentina

We report the southernmost record of Yellow-headed Vulture, Cathartes burrovianus, in Punta Piedras, north-eastern Buenos Aires province, Argentina. This record implies the presence of this species in a new habitat: the Pampas ecoregion. Considering this and other records in Argentina and Uruguay, the species distribution could be extending south from its known range.


Introduction
The genus Cathartes Illiger, 1811 comprises 3 species of New World vultures.They are large, scavenger birds that locate their food using a well-developed sense of smell (Graves 1992).Alongside the other members of the family Cathartidae, they play an important role in their ecosystems, finding carcasses and removing carrion (Houston 1994).
The Lesser Yellow-headed Vulture, Cathartes burrovianus Cassin, 1845, lives mainly in tropical and subtropical regions, ranging from Mexico to Panama and from Colombia to north-eastern Argentina and Uruguay (Houston 1994, Ferguson-Lees andChristie 2001).Although it is a common and fairly recognizable bird, its status and distribution are not well established, particu-larly concerning the southern subspecies, C. burrovianus urubutinga Pelzeln, 1861 (Houston 1994, Campbell 2005).In Argentina it is usually found in humid regions in the north-east, within Dry and Wet Chaco ecoregions (Paulini et al. 2015), reaching Entre Ríos province at its southern limit (de la Peña 1996, Aves Argentinas 2009, Marateo et al. 2009) (Fig. 1).It can be found in open wet grasslands and marshes, and less frequently in forest edges (Houston 1994, Eitniear andMcGehee 2017).
One individual of a Lesser Yellow-headed Vulture was feeding on a dead Big Hairy Armadillo, Chaetophractus villosus (Desmarest, 1804), which had previously been hit by a car.The bird flushed due to our close presence but then returned to a nearby post and stood still while we photographed it (Fig. 2).The sighting occurred along an unpaved road bordered by trees and fences.
Identification.The individual seen was a large, darkbrown bird, with the ventral side of the remiges almost white.Its head was completely bald and the nostrils were perforated.The upper middle of the head was pale blue.The nose was red.The cheeks, which were crossed by a black stripe, were bright yellow (Fig. 2).The brownish tone of the feathers helped us to differentiate it from the more unlikely Greater Yellow-headed Vulture, C. melambrotus Wetmore, 1964, and the head color pattern was enough to discard the more common Turkey Vulture, C. aura (Linnaeus, 1758).

Discussion
This is the southernmost record for the Lesser Yellowheaded Vulture, being approximately 270 km south from the closest documented records in Argentina (Marateo et al. 2009, Aves Argentinas 2009) (Fig. 1).This observation also represents the first published record for the species in Buenos Aires province.In Uruguay, the Lesser Yellow-headed Vulture is usually considered as a resident, but there is little information available concerning its distribution, and few exact locations are described in literature (Tremoleras 1927, Cortés et al. 2013).In addition to our find and the previous published data, there are some recent records from online databases, such as eBird (https://ebird.org/)and EcoRegistros (https:// ecoregistros.org/)for Entre Ríos and Buenos Aires provinces, and also for southern Uruguay, suggesting that the range of this species may be extending south from its traditionally known distribution (Fig. 1).All these records together undoubtedly show a scarce but regular presence of this species in areas far south of its published range.
Previous records in Argentina are from warmer ecoregions mainly dominated by forests and with mean annual temperatures from 18 °C to 25 °C (Morello et al. 2012).Our record is located within the Pampas ecoregion, which is a new habitat for the species.This ecoregion is characterized by grasslands, with an extreme anthropogenic modification due to the advance of agriculture, and has mean annual temperatures from 15° to 20°C (Morello et al. 2012).
Some vulture species are known to have expanded and grown their populations by associating with human activities, such as cattle, landfills, or urban settings, where they find food and habitat diversity (Avery 2004, Novaes andCintra 2015).Even though cattle is a main activity in northern Buenos Aires province (Morello et al. 2012), Cathartes vultures usually feed on smaller prey (Houston 1994, Campbell 2015, Novaes and Cintra 2015).On the other hand, new sanitary landfills and illegal waste disposal areas may provide vultures with new feeding opportunities (Novaes and Cintra 2015).However, there is a lack of information about solid waste disposal in all of Latin America (Tello Espinoza et al. 2010), which makes it difficult to track these places and survey the fauna associated with them.
Vultures are great flyers that can cover large distances with little effort (Houston 1994), and occasional records may simply be more evident because in recent years there has been an increase of birdwatchers uploading data to platforms such as eBird (Sullivan et al. 2014) and EcoRegistros.
Finally, global climate change can also lead to changes in species distributions (Parmesan and Yohe 2003).In this sense, Chen et al. (2011) found that the distributions of many species have recently shifted to higher latitudes as a consequence of the global warming.Therefore, reporting new locations and reviewing the distribution of Neotropical birds can be important to understanding ecological changes.