Urbanization enhances ornament expression in a common waterbird
Data files
Jun 04, 2025 version files 112.44 KB
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Raw_Data_1.xlsx
53.88 KB
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Raw_Data_2.xlsx
22.95 KB
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Raw_Data_3.xlsx
31.56 KB
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README.md
4.06 KB
Abstract
In birds, many components of visual communication (i.e. plumage and non-plumage ornaments) play an important role in signaling of individual quality. It is widely acknowledged that ornament expression may be modulated by environmental conditions, however, it remains relatively poorly explored whether and how urbanization affects the expression of non-plumage ornamentation in urban dwelling-individuals. Here, we investigated the effect of urbanization on the expression of bare-part (non-plumage) putative ornament (i.e., the frontal shield size) across eight populations of a common reed-nesting waterbird, the Eurasian coot Fulica atra. Most importantly, we found robust support for the positive effect of urbanization on shield size and its condition-dependent character in coots. Also, long-term monitoring of a single urban population revealed relationships between the ornament expression and nest site selection patterns, as coots with larger shields were bold enough to colonize more anthropogenically transformed urban sites with stronger human disturbance and better accessibility to anthropogenic food. At the same time, we found no support for associations between the shield size and either nest defense behavior or reproductive performance in coots, likely reflecting stochasticity of anthropogenic selective pressures. To our knowledge, this study provides the first evidence for the enhanced expression of an unpigmented non-plumage putative ornament in urban-dwelling birds. Our results show that the effects of urbanization on non-plumage components of quality signaling in birds may be complex and multifaceted, and reinforces a need for further investigation focusing on different types of ornamentation across divergent avian species.
Description of the data and file structure
Files and variables
Description:
File: Raw_Data_1.xlsx
The data on frontal shield size, condition, and physiological stress were collected for 485 Eurasian coots (541 capture occasions) from eight paired populations (four urban and four nonurban) across Poland during 11 breeding seasons (years: 2012 - 2023).
File: Raw_Data_2.xlsx
The data on nest defence behaviour were collected for 128 Eurasian coots (204 experiments) from one urban population (Łódź) during 11 breeding seasons (years: 2012 - 2023).
File: Raw_Data_3.xlsx
Data on nest site selection and reproductive performance were collected for 182 Eurasian coots (211 breeding attempts) from one urban population (Łódź) during 11 breeding seasons (years: 2012 - 2023).
Variables
- ID: Individual identity.
- Capture date: Date of bird capture and measurement collection (day of the year).
- Urbanization: The level of urbanization (Urban - an individual was sampled from one of the four urban populations, Nonurban - an individual was sampled from one of the four nonurban populations)
- Population pair: The population pair from which the individual was sampled (Warszawa, Poznań, Katowice, Łódź).
- Year: The year in which the individual was captured and measured.
- Sex: The sex of the individual (F - female, M - male).
- Wing length (mm): The wing length was measured from the carpal joint (the bend of the wing) to the tip of the longest primary feathers with a stopped ruler. Wing length was included as a linear predictor of body mass in the statistical models.
- Frontal shield size (PC1): The shield size was calculated using two measurements (length and width), which were combined into a single univariate parameter (PC1) using principal component analysis (PCA). PC1 was standardised to z scores separately for males (M) and females (F).
- Body mass (g): Body mass was measured using an electronic balance.
- Haemoglobin concentration (g/l): Haemoglobin concentration, used as condition index, was measured with HemoCue Hb 201+ portable photometer.
- Size-corrected body mass: Size-corrected body mass, used as condition index, was calculated as Scaled Mass Index (SMI) according to Peig and Green (2009).
- H/L ratio: The H/L ratio (used as physiological stress index) was calculated as the proportion of heterophils (H) to lymphocytes (L).
- Experiment date: Date of the experiment (day of the year).
- Breeding status: Breeding attempts of captured birds, including first and second or renest (repeated after brood failure) broods, coded as a binary trait (0 - first brood; 1 - second/renest brood).
- Incubation stage (days): The interval between the laying date and the date of the experiment.
- Nest defence - presence: The presence or absence of aggressive nest defence (approach with threat posture, alarm vocalization, or splattering display) against a human intruder (experimenter) at the nest site (coded as binary trait: 0 - absence of nest defence, 1 - presence of nest defence).
- Nest defence - approach distance (m): The minimum distance at which a bird approaches human intruder (experimenter) during nest defence at the nest site.
- Laying date: Date of laying the first egg (day of the year).
- Distance from nest to shore (m): The distance from the nest to the shore.
- Distance from nest to open water (m): The distance from the nest to the open water (set to zero if the nest was located outside emergent vegetation).
- Water depth (m): The water depth at the nest.
- Clutch size: The number of laid eggs.
- Hatching success: Hatching of at least one chick (1) or hatching no chicks (0).
- Breeding success: Raising (fledging) of at least one chick (1) or rasining no chicks (0).
- No. raised chicks: The number of raised chicks assessed visually (with binoculars) for all broods after 4-6 weeks from hatching.
Missing values marked as "NA".
Code/software
All computations were performed in R v.4.2.3 statistical environment.