Territorial aggression and coexistence in hybridizing Campylorhynchus: Disentangling the roles of climate, resource availability, and species interactions in Western Ecuador
Abstract
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.
https://doi.org/10.1101/2023.10.13.562238
Description of the data and file structure
This dataset documents territorial aggression in two hybridizing wren species, Campylorhynchus zonatus brevirostris (BBWR) and Campylorhynchus fasciatus pallescens (FWR), through standardized playback experiments conducted in western Ecuador in 2018. The study encompasses 112 distinct experiments performed on separate breeding groups, with a minimum spatial separation of 400 meters between tested groups to ensure independence of observations.
Each experiment followed a structured protocol consisting of a control and two treatment periods, with intervening breaks. During control periods, researchers broadcast a song of a non-territorial bird species (Elaenia flavogaster) that typically does not elicit territorial responses. Treatment periods involved playback of territorial songs from either the same species (intraspecific treatment) or the other focal species (interspecific treatment), allowing for direct comparison of response intensity across different contexts.
For each experimental trial, the observer systematically recorded multiple response variables that quantify territorial aggression, including:
Minimum approach distance to the speaker (horizontal, vertical, and direct distance in meters)
Latency (time elapsed from playback initiation until response, measured in seconds)
Specific aggressive behaviors and vocalizations (documented as Fixed Action Patterns or FAPs)
Number of responding individuals within each breeding group.
File:
Data.csv: Contains the primary experimental data, including all behavioral responses observed during playback trials. This file documents 4,905 observations across 15 variables, recording each Fixed Action Pattern (FAP) exhibited by the birds, the timing and distance measurements of these responses, the number of individuals responding, and contextual information about each observation. This dataset forms the core of the analyses presented in the associated article.
Variables in Data.csv:
Experiment identifier code: Unique code for each experiment.
Treatment: Type of playback treatment used. Categories include Setting (preparation phase), Break (3 minutes of silence), Control (3 minutes of non-territorial bird songs), Intraspecific (3 minutes of the same species playback), and Interspecific (3 minutes of the other species playback).
- BBWR: Treatment playing Band-back Wren (Campylorhynchus zonatus).
- FWR: Treatment playing Fasciated Wren (Campylorhynchus fasciatus).
Code: Identifier for the song used in the playback experiment. Metadata is available in the associated publication in the Journal of Avian Biology.
Scientific: Scientific name of the tested species or non-target species observed nearby.
FAP: Observed Fixed Action Pattern (see associated paper for full ethogram).
| Code | Description |
|---|---|
| BC | Noise produced by bill clapping, normally less than one second in duration |
| Cl | Short and simple sounds, at least two types were recognized, a rasp (tjak) and a kee sound |
| Si | Long and complex sound, it may last several seconds in duration and can be produced in duets |
| Ha | Hanging with the head down |
| MT | Changing perch in the same tree, involves hopping or short flights less than 1 m in distance within the same tree |
| ST | Changing perch moving to a different tree or making movements longer than 1 m in distance within the same tree, involves just flights |
| STS | Involves the same action as “Switching Trees” but sings at the same time |
| Sal | Makes a wing-powered, flycatcher-type motion after which the bird leaves and returns to the same perch, used as a direct attack to the speaker |
| Sk | Perches on the speaker, unusual |
| Ho | Small jumps on the ground, generally toward the speaker |
| DA | A bill or claw hit at another bird with a jump or short flight, directed at an individual of the same group or another group that also responded to the playback, often occurs with a rasp calling |
| Fo | Leg-powered movement, walking along branches while reaching out for food items among vegetation |
| Gr | Grooming feathers with the bill on itself or a conspecific |
| Pe | No wing or leg-powered movement stays on the same perch |
| BCl | Rubs the bill against a surface, usually after eating a food item |
| Po | Ejects feces while perching. This is not considered aggressive as it is also performed outside of a territorial aggressive context. |
Inv: Number of individuals in the breeding group responding to the stimuli.
Timing: Time elapsed (in minutes) from the start of the treatment until the FAP was observed.
Timing_sec: Timing variable converted to seconds.
Sec: Seconds remaining to end the treatment.
HorDist: Horizontal distance (meters) from the speaker where the FAP was observed.
VertDist: Vertical distance (meters) from the ground where the FAP was observed.
Dist: Straight-line distance (meters) from the speaker where the FAP was observed.
Observation: Additional comments or noteworthy observations from the experiment.
Missing Data (NA values)
NA values in the dataset correspond to response variables that were not recorded during experimental breaks or setup phases. These include FAP, Inv, Timing, Timing_sec, Hor.Dist, Vert.Dist, and Dist. In rows where these phases occurred, NA values are present.
The dataset is complemented by detailed supplementary materials available in the associated research article, including:
- Complete metadata for all bird sound recordings used as playback stimuli
- Comprehensive experimental protocols and setup parameters
- A detailed ethogram describing and defining all Fixed Action Patterns (FAPs) observed during the study
UR (Unresponsive)
This code indicates that no behavioral response was observed during a specific moment. When observers confirmed that individuals were present but did not exhibit any detectable reaction to the stimulus being presented, “UR” was recorded in the data. This differs from “NA” values, which indicate that no observation was attempted (such as during breaks or setup periods).
These data collectively enable investigation of how hybridization, climate variables, and resource availability influence territorial behavior in these closely related tropical bird species, providing insights into the mechanisms that facilitate coexistence in hybrid zones.
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.