Diet of birds in Polylepis quadrijuga (Rosaceae) forests in the Rusia páramo, Duitama (Boyacá, Colombia)

Abstract

Birds are species known for maintaining ecological balance through pollination and seed dispersal. They can also be biological controllers through their ingestion of arthropods, making them an important link in the terrestrial food chain. This study conducted a general characterization of the diet of birds in Polylepis quadrijuga forests of the Páramo de la Rusia (Russian Paramo), based on feces and pollen samples collected from birds captured with mist nets in three forests with similar physiognomic characteristics. Two sampling techniques were used: capture with mist nets and direct observation. Captured birds were placed in cloth bags, where their feces were collected. Pollen was also collected from the birds' beaks using transparent tape or glycerinated gelatin. This procedure was carried out in each forest for 30 days. A total of 120 individuals were recorded, distributed across 39 bird species, with the Trochilidae family being the dominant one, followed by Emberizidae. Twenty-seven fecal samples were analyzed, of which 62.9% contained only invertebrates, 22.2% only seeds, and 14.8% both invertebrates and seeds. The birds' dietary preferences for plant sources are represented in the Ericaceae family, both in seeds and pollen (29 pollen samples). Likewise, invertebrates of the Coleoptera and Hymenoptera orders were the most abundant. Birds feed on the vegetation associated with polylepales; however, given the limited supply of this resource, they seek other food sources.