Variation in abundance and habitat relationship of three understory insectivorous birds in a disturbed landscape of Neotropical dry forest of Colombia

Background Evaluating relationships between avian populations and their habitat is important for understanding the biology of these species and for management decisions that improve the effectiveness of restoration practices. We investigated how habitat variation along a disturbance gradient affected the abundance of three insectivorous bird species, White-bellied Antbird (Myrmeciza longipes), Barred Antshrike (Thamnophilus doliatus), and Pale-breasted Spinetail (Synallaxis albescens) in a Neotropical dry forest remnant in central Colombia.

Methods The study area, which is located in Magdalena Valley, is under ecological restoration after the construction of the "El Quimbo" hydroelectric dam, with a gradient of habitat conditions, from relatively advanced secondary growth to recently disturbed areas. We conducted bird surveys and quantified the habitat conditions from June 2018 to June 2019. We compared the relative abundance of the birds among the three zones with increasing disturbance and modeled the relationship between the bird abundance with the micro- and landscape-habitat conditions, with Poisson generalized linear model regression.

Results The relative abundance of the three bird species varied according to the habitat features and disturbance level. The abundance of White-bellied Antbirds was higher in forests and thickets than shrubland fragments; Barred Antshrike was more abundant in shrubland and thickets than in forest fragments, and Pale-breasted Spinetail had the highest abundance in shrubland and the lowest in forest fragments. The abundance of both White-bellied Antbird and Pale-breasted Spinetail did not differ among zones with different levels of disturbance, while the abundance of Barred Antshrike decreased in zones with more disturbance.

Conclusions There were significant differences in the habitat relationships of the three understory insectivorous species along the disturbance gradient, although these species were within the same trophic group. These bird species preferred different stages of habitat succession and responded to different habitat and landscape features. Increasing forest fragment areas and decreasing the amount of edge would be useful restoration priorities for these and other similar avian species in this study area.