The genus Knipolegus (Passeriformes: Tyrannidae) comprises 12 described species, which inhabit a wide variety of environments in South America (Hosner and Moyle, 2012; Schultz, 2022). Ten species occur in Brazil, seven of which are residents (Las-Casas and Azevedo-Junior, 2008). Three species have been recorded in the Caatinga domain: K. lophotes (Boie, 1828), K. franciscanus (Snethlage, 1928), and K. nigerrimus (Vieillot, 1818), with K. nigerrimus showing the largest distribution in the region (Silva, 2017). In the Caatinga, a phytogeographic domain that predominantly covers the semi-arid Northeast, extending as far north as Minas Gerais (Silva et al., 2017), K. nigerrimus has been recorded in the following states: Bahia, Alagoas, Ceará, Pernambuco and Paraíba (Sick, 1997; Farias et al. 2006; Las-Casas and Azevedo-Junior, 2008; Araujo et al., 2012) at altitudes between 560m and 1000m. Here, however, we describe a new record of K. nigerrimus in the Caatinga at a lower altitude than previously reported in the literature.
K. nigerrimus was recorded during bird sampling studies conducted at Fazenda Aba (Fig. 1), a private property located in the Depressão Sertaneja Setentrional (IBGE, 2021), in the municipality of Passagem, Paraíba, Brazil (07°05 ̓50"S, 37°01 ̓34"W). This location is characterised by its Caatinga vegetation, the presence of rocky walls at altitudes ranging from 300 to 810m, as well as springs and perennial water bodies (Fernando et al., 2021; 2022; Medeiros, 2022). The climate of the region is hot and dry, with an average annual temperature of 25°C (Francisco et al., 2015).
The individual was recorded during a morning excursion at approximately 8:12am on 23 October 2022. An adult male was observed near a rocky wall in a canyon at an altitude of approximately 290 m. Its behaviour consisted of short flights, followed by immediate landings on the rocky surfaces where it was. The specimen was identified based on its morphological and vocalisation characteristics. During the observation period, a photographic record of the individual was taken for documentation (Fig. 2), which was essential for subsequent analysis. A Canon PowerShot SX50 HS camera was used as the photographic equipment.
The individual K. nigerrimus, identified as an adult male, was making short-distance flights in the vicinity of rocky walls, located in a canyon region, taking off and landing on the same rocks. In addition, this location is approximately 290 m above the sea level. Several diagnostic characteristics were analysed to identify the species in question. The plumage, which consists of a predominantly black colouration, is its most distinctive feature: the presence of a hidden white band on the remiges, observed in flight, the rudimentary crest, tonal variations of the beak, lighter at the base and darker at the tip, and body size, as few species in the region have the same dimensions and colouration. The determination of the individual's sex was made by the absence of a brown spot in the gular area, which is exclusive to females of this species (Fig. 3).
K. nigerrimus is distributed across states in the southern, southeastern, and northeastern regions of Brazil, where it inhabits forested areas and high-altitude grasslands, transitioning between these habitats (Sick, 1997). It is a bird that exhibits a dependency on high altitudes, ranging from 700 to 2,700 meters, and is even classified as endemic to these regions (Sigrist, 2006).
The present record describes an individual at an altitude of 290 meters, which constitutes an atypical occurrence for the species. The specimen in question was found near a perennial watercourse that crosses Fazenda Aba. One possibility for this distribution at an unusual altitude could be the search for water, following the individual's descent from higher elevations in the region.
Another possible explanation for the event described here is related to the reproductive biology of the species, as the observed behaviour in our study resembles that described by Pichorim et al. (1996). In their description, despite the female being responsible for egg care, the male remains perched on rocks or shrubs nearby, approximately 8–15 m away from the nest, occasionally flying to ward off individuals from other species. The date of our record aligns with that of the reproductive period of the species recorded by Pichorim et al. (1996), which occurs between October and November. Although some crevices were observed along the rocky wall, we did not observe other K. nigerrimus individuals near the recording location, making it impossible to confirm the presence of a nest in the area.
The fact that the reported event is based on a single record, coupled with the lack of information in the literature regarding the biology, ecology, and behaviour of K. nigerrimus, limits the possible conclusions regarding the occurrence of the species at such an atypical altitude, as observed in our study. This singular record is, therefore, of great significance as it offers a unique perspective on possible adaptive behaviours of K. nigerrimus and expands the species' distribution in the Caatinga. However, further studies involving the responses of species to seasonal fluctuations, as well as reproductive behaviours, are necessary, not only in the Caatinga, but throughout Brazil.