Territorial aggression and coexistence in hybridizing Campylorhynchus: Disentangling the roles of climate, resource availability, and species interactions in Western Ecuador

This dataset documents behavioral responses from standardized playback experiments investigating territorial aggression between two hybridizing tropical bird species, Campylorhynchus zonatus brevirostris (BBWR) and Campylorhynchus fasciatus pallescens (FWR), conducted in western Ecuador in 2018. The data collection focused on three distinct genetic populations: C. z. brevirostris, C. f. pallescens North (admixed population), and C. f. pallescens South (non-admixed population).

The dataset consists of a CSV file:

Data.csv: Contains 4,905 detailed behavioral observations from 112 playback experiments, including approach distances (horizontal, vertical, and direct in meters), response timing (in seconds), specific behavioral responses (Fixed Action Patterns), and number of responding individuals.

The experimental design systematically tested responses to both intraspecific (same-species) and interspecific (different-species) territorial songs, with appropriate control periods using non-territorial bird songs. Each experiment followed a structured protocol of a control and two treatment periods with intervening breaks. All experiments maintained a minimum spatial separation of 400 meters between tested breeding groups to ensure independent observations.

This comprehensive dataset enables researchers to examine how hybridization, climate factors, and resource availability interact to shape territorial aggression and coexistence in tropical bird communities. The data can be used to test hypotheses about interspecific territoriality, asymmetrical aggression patterns, and environmental influences on territorial behavior in hybridization zones. Detailed supplementary information, including a complete ethogram of observed behaviors and metadata for sound recordings used as stimuli, is available in the associated publication.

Methods
The data used to test our hypotheses come from 112 playback experiments carried out between June and November of 2018. Breeding groups (a.k.a. groups) were tested only if they were at least 400 m apart from any other group already tested to maintain independence among group responses. Playback experiments were carried out after confirming auditorily or visually the presence of a group or individual. Recordings were played using a wireless UE BOOM 2 speaker. The observer kept a distance of at least 15 meters from the speaker during the experiments. The experiments consisted of the following steps.

Initial observations: We annotated the context setting of the experiment, including group size, the distance at which the group was first observed, other species present at the moment, habitat description, and coordinates.
Control: We played three minutes of the songs of Elaenia flavogaster obtained from Xenocanto. Yellow-bellied Elania occurs on edges and clearings along Western Ecuador (Ridgely and Greenfield 2006) in syntopy with both species.
Break 1: We recorded any changes in the context setting compared to the initial observation for three minutes.
Treatment 1: We played three minutes of C. z. brevirostris or C. f. pallescens South alternating the order for each group encountered.
Break 2: We recorded changes in the setting or behaviors of the group.
Treatment 2: We played three minutes of C. z. brevirostris or C. f. pallescens South alternating the order according to what was played in treatment one.
Break 3: We recorded group behaviors whenever observed, including any changes in the variables measured during initial observations.