DOI: 10.5061/dryad.vt4b8gv3j
title: Data from: Influence of mate and nest-site fidelity on a declining, urban avian population

description: As urbanization reduces species’ habitats and population sizes, managers
 need information on whether within-population processes, such as changes
 in mate and nest-site fidelity and dispersal distances, may be
 contributing to declines. We investigated whether mate fidelity, nest-site
 fidelity, or breeding dispersal distance changed over time in a population
 of burrowing owls (Athene cunicularia), a short-lived, socially-monogamous
 species. During the 18-year period of the study, the population declined
 by 69% in urban Santa Clara County, California, USA--a region of rapid
 urbanization. We assessed whether these behaviors were influenced by key
 factors including age, breeding success in the previous year, and years
 with the same mate, and examined the relationship between mate and
 nest-site fidelity over time and annual reproductive success. To evaluate
 the relationship between mate and nest-site fidelity as well as overall
 mate and nest-site fidelity rates by sex, we used Chi-Square tests. For
 all other tests, we used Generalized Linear Mixed Models (GLMM) with
 individual bird identification as a random variable to address the
 inclusion of the same birds in multiple years. Our analyses showed no
 change over time in mate fidelity, nest-site fidelity rates, dispersal
 distances, or annual reproductive success, indicating these behaviors
 remained stable even during a severe population decline. Although
 burrowing owls are a short-lived species, we found that increasing years
 with the same mate resulted in increased mate fidelity, nest-site
 fidelity, and annual reproductive success. Since these fidelity behaviors
 were maintained during the population decline, other factors require
 investigation to determine the causes for decreases in numbers in this
 population. Thus, even species such as burrowing owls, which can maintain
 important fidelity behaviors in urban setting, are still subject to other
 pressures that can cause population declines.
description: # Influence of mate and nest-site fidelity on a declining, urban avian
 population Dataset DOI: [10.5061/dryad.vt4b8gv3j](10.5061/dryad.vt4b8gv3j)
 ## Description of the data and file structure Our objective was to
 investigate mate and nest-site fidelity rates and breeding dispersal
 distances in relationship to reproductive success in an avian population
 declining in an urban setting.  Given that urban settings can disrupt mate
 selection and/or the longevity of nesting sites, we suspected that mate
 and nest-site fidelity rates might change significantly as the study
 population decreased.  Disruption of these behaviors could then contribute
 to the declining population through reduced annual reproductive success
 over time.  We analyzed mark-resight data for a population of resident
 western burrowing owls (*Athene cunicularia subspp. hypugaea*) over an
 18-year period in Santa Clara County, California, an area of rapid
 urbanization [38].   ### Files and variables #### File:
 BUOW\_Fidelity\_Behavior\_Data.xlsx **Description:**   We conducted all
 statistical analyses using SPSS (v.28; IBM Corporation).  The α-level for
 significance was 0.05. Continuous variables included year, age, dispersal
 distance, years with the same mate, and annual reproductive success as
 measured by emergent brood size (number of chicks per brood).  Categorical
 variables were mate fidelity (yes or no), nest-site fidelity (yes or no),
 breeding success the previous year (yes or no), sex (male or female) and
 individual bird identification number. To evaluate the relationship
 between mate and nest-site fidelity as well as overall mate and nest-site
 fidelity rates by sex, we used Chi-Square tests. For all other tests, we
 used Generalized Linear Mixed Models (GLMM) with individual bird
 identification as a random variable to address the inclusion of the same
 birds in multiple years.  Relationships between mate fidelity or nest-site
 fidelity and factors that could influence those rates were tested with
 using a Binary Logistic distribution.  The Gamma distribution (log link)
 was used to compare male to female dispersal distances and for hypotheses
 testing factors potentially affecting breeding dispersal distances, which
 was right-skewed, continuous data.  Finally, we used the Poisson
 distribution (log link) to test hypotheses with number of chicks per brood
 (annual reproductive success), which were count data and to compare the
 annual reproductive success of birds that did versus did not show mate or
 nest-site fidelity and compare years with the same mate by sex. #####
 Variables * year * age (year) * dispersal distance (meters) * years with
 the same mate * annual reproductive success (number of chicks per brood) *
 mate fidelity (yes or no) * nest-site fidelity (yes or no) * breeding
 success the previous year (yes or no) * sex (male or female) * individual
 bird identification number ## Code/software We conducted all statistical
 analyses using SPSS (v.28; IBM Corporation).  Specific details for
 analyses using each spreadsheet in the data file are as follows: 1. To
 separate males from females, use the "Sex of Primary Mate"
 column 2. Y=Yes, N=No, S=Successful, F=Failed 3. In all GLMM tests, use
 PrimaryMate_ID (individual bird identification) for the random variable.
 4. Missing data: Cells will be empty when the outcome was unknown for that
 year for that variable. | **Spreadsheet Name** | **Description** | **Tests
 with this Data Set** | | :------------------------ |
 :---------------------------------------------------- |
 :-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | MateFidelity | Mate Fidelity Records (categorical data: Y or N) | 1) Chi-square for relationship between Mate and Nest-site Fidelity; 2) Chi-square for relationship between Mate Fidelity and Sex; 3) GLMM (Binomial Logistic Regression) with these variables: Year, Age and Breeding success the previous year (select S and F) | | NestSiteFidelity | Nest Fidelity Records (categorical data: Y or N) | 1) Chi-square for relationship between Nest-site Fidelity and Sex; 2) GLMM (Binomial Logistic Regression) with these variables: Year, Age, Breeding success the previous year (select S and F) and Years with same mate | | BreedingDispersal | Breeding Dispersal Distance Records (continuous data) | 1) GLMM (Gamma, log link; add 1 to each enty to eliminate 0s) to compare male to female dispersal distances;        2) GLMM (Gamma, log link; add 1 to each enty to eliminate 0s) with these variables: Year, Age, Breeding success the previous year (select S and F) and Years with same mate | | AnnualReproductiveSuccess | Brood Size Data Records (continuous data) | 1) GLMM (Poisson distribution, log link) to compare birds that did or did not show mate or nest-site fidelity and compare years with the same mate by sex; 2) GLMM (Poisson distribution, log link) with these variables: Year, Age and Years with same mate (remove Years\_with\_Mate=5; only 2 records) | | NatalDispersal | Natal Dispersal Distance Records (continuous data) | Natal Dispersal Distance descriptive statistics | ## Access information Other publicly accessible locations of the data: * None Data was derived from the following sources: * No additional sources; data were collected by the study authors