Sociability Linked to Reproductive Status Affects Intestinal Parasite Infections in the Red-Billed Chough

Area of Science:

• * Avian ecology and wildlife parasitology.
• * Investigating the interplay between social behavior, host condition, and parasite transmission in wild bird populations.

Background:

• * Red-billed choughs (Pyrrhocorax pyrrhocorax), a declining corvid species, exhibit distinct social structures based on reproductive status.
• * Non-breeding individuals form communal roosts in winter, while breeding pairs maintain territories and roost at nesting sites.
• * Social behavior is increasingly recognized as a critical factor influencing disease dynamics in wildlife.

Purpose of the Study:

• * To determine if differences in sociality (communal roosting vs. territorial pairs) influence intestinal parasite infections in red-billed choughs.
• * To assess parasite prevalence and intensity in relation to social aggregation and territoriality.
• * To explore the implications of social structure for conservation strategies targeting threatened bird species.

Main Methods:

• * Collection of fresh fecal samples from non-breeding and breeding red-billed choughs during winter in central Spain.
• * Analysis of fecal samples using flotation and McMaster techniques for coccidian oocysts and helminth eggs.
• * Quantification of parasite loads and comparison between communally roosting non-breeders and territorial pairs.

Main Results:

• * High prevalence of coccidian oocysts (36.2%) and low prevalence of helminths (9.5%) detected in communally roosting non-breeders.
• * No intestinal parasites were detected in fecal samples from territorial pairs, though sample size was limited.
• * One communal roost exhibited a higher coccidian positive rate, potentially linked to roost structural features promoting parasite transmission.

Conclusions:

• * Social structure significantly influences intestinal parasite infection risk in red-billed choughs, with communal roosting associated with higher parasite loads.
• * The absence of parasites in territorial pairs may indicate better host condition and immune function, alongside reduced exposure.
• * Non-invasive parasite monitoring and consideration of social behavior are crucial for effective conservation of threatened avian populations.