DOI: 10.5061/dryad.pnvx0k6vm
title: Extra-pair paternity enhances the reproductive fitness of urban Chinese blackbird

description: Urbanization is a human-induced process of rapid habitat change that can
 affect the reproductive success of animals. The occurrence of
 extra-partial paternity (EPP) may be sensitive to changes in urban
 ecological conditions. In this study, the Chinese blackbird (Turdus
 mandarinus), a common breeding bird in southern Chinese cities, was
 selected as the focus species to explore the EPP patterns of monogamous
 birds in developing cities and their relationship. Over four breeding
 seasons, 316 Chinese blackbird nestlings and 20 adults in both urban and
 rural areas were monitored and genotyped for 11 microsatellite loci to
 determine progeny affinity. We confirmed that both the brood size and
 hatching rate of EPP nests were significantly larger than those of
 within-pair paternity (WPP) nests. The body mass, beak length, head
 length, and body length of 12-day age extra-pair offspring (EPO) were
 significantly greater than those of within-pair offspring (WPO) suggesting
 important benefits of EPP. However, according to the analyses of nest
 ecological variables, we concluded that EPP occurs most often in areas
 with low urbanization levels indicating some constraints for this
 reproductive strategy in cities. Our findings provide interesting new
 insights into how this growing human-induced landscape change affects
 mating behavior in birds, an important aspect of avian ecology and
 evolution.
description: This README.txt file was generated on 2023-12-25 by Zhang Xueli   GENERAL
 INFORMATION 1\. Title of Dataset: Data from: Extra-pair paternity enhances
 the reproductive fitness of urban Chinese blackbird Date of data
 collection: 2017 -- 2022 Geographic location of data collection: We
 monitored the breeding of Chinese blackbird in Nanchang city (Qianhu
 Campus of Nanchang University, 28°10’ – 29°11’N,115°27’ – 116°31’E) and
 Yugan County of Shangrao City (including Dashandi village, Chaijiashan
 village, and Dongjiadian village; 28°21’ – 29°3’N, 116°13’ – 116°54’E),
 Jiangxi Province, China, during the 2017 – 2020 breeding seasons.   DATA
 & FILE OVERVIEW 1\. Description of dataset A total of 164 breeding
 nests (≥ 1 egg) were located and traced until the breeding activity.
 Parent analysis was performed on 316 nestlings from 89 successful breeding
 nests (≥ 1 nestling) and 20 parental individuals (11 females and 9 males)
 from 17 breeding nests. A dataset of 20 nests was removed from further
 analyses as they had only one nestling per nest. Subsequently, a total of
 284 nestlings were used for the relatedness analysis. In total, 50 EPO
 were detected in 44 EPP nests. 2\. File List: File 1 Name: GLM model File 1
 Description: The comparative estimation of nest habitat variables between
 Chinese blackbird's extra-pair paternity (EPP, n=44) nests and
 within-pair paternity (WPP, n=24) nests is based on independent sample
 t-test data. File 2 Name: LMM model File 2 Description: offspring type: 1
 = extra-pair offspring, 0 = within-pair offspring. When the nestlings
 reached 5 day of age, six physical parameters (including body mass, body
 length, head length, wing length, tarsus and body length) of the nestlings
 were measured. File 3 Name: Reproductive File 3 Description: The
 comparison of reproductive parameters between the Chinese
 blackbird's extra-pair paternity (EPP, n=44) nest and within-pair
 paternity (WPP, n=25) nest is based on the original data of independent
 sample t-test. File 4 Name: SSR File 4 Description: All amplification
 products were analyzed on an ABI 3100 capillary DNA automatic sequencer.
 Fragment sizes were determined using ABI GENESCAN software based on the
 internal lane standard GeneScan 500 [Rox]. Allele sizes were scored by ABI
 GENEMAPPER 3.7. ID = offspring. DATA-SPECIFIC INFORMATION FOR: GLM mode
 1\. Number of variables: 9 2\. Number of cases/rows: 69 3\.
 Column List: num, type, NTV, HV, SSUS, LSUS, NV, CV, RV 4\. Missing data
 codes: none 5.abbreviations used: * num = ordered * Type = 1 for
 extra-pair paternity nests and 0 for within-pair paternity nests * NTV =
 nest tree variables. It includes Ground diameter, Nest tree height, Nest
 height and Diameter of the tree canopy. * HV = hidden variables.
 It includes Percent of canopy cover, Concealment and Percent crown cover
 of nest. * Percent of canopy cover is Projection ratio of nest tree crown
 on the ground. * CV = competition variables. It was minimum spacing of the
 intraspecific nest. * SSUS = Small-scale urbanization score. To obtain
 SSUS at nest sites, we measured the degree of urbanization with the
 following relevant components for birds : number of floors, building
 coverage, vegetation coverage, percentage of impervious surfaces,
 and distance of nest from light. For SSUS, we examined circular samples
 with the nest site as the centre, using the minimum intraspecific nest
 spacing of the bird (40 m) as the diameter of the circle. According to an
 analysis of satellite tracking data of Chinese blackbirds during their
 breeding period, their domain range was estimated to be a circular area
 approximately 400 m in diameter. * LSUS = Large-scale urbanization
 score. To obtain LSUS at the nest sites, we examined circular samples with
 the nest site as the centre and the home range diameter of the bird as the
 diameter, and calculated building coverage, vegetation coverage, and
 percentage of impervious surfaces (Liker et al. 2008). * RV = Resource
 variables. It is distance of nest from water sources. * NV = Nest
 variables. It includes Position of the nest, Nest outside diameter, Nest
 inside diameter and Nest depth. DATA-SPECIFIC INFORMATION FOR: LMM model
 1\. Number of variables: 8 2\. Number of cases/rows: Sheet1:Body mass 74,
 Sheet2: Beak length 74, Sheet3: Head length 73, Sheet4: Tarsus length 74,
 Sheet5: Wing length 74, Sheet6: Body length 74 3\. Variable List: body
 mass(g), beak length(mm), head length(mm), tarsus length(mm), wing
 length(mm), and body length(mm), offspring type, nest ID. 4\. Missing data
 codes: none 5\. abbreviations used: none DATA-SPECIFIC INFORMATION FOR:
 Reproductive 1\. Number of variables: 7 2\. Number of cases/rows: 70 3\.
 Variable List: clutch size, brood size, fledgling number, hatching rate
 (%), hatching rate (%), reproductive success rate (%) 4\. Missing data
 codes: 5\. abbreviations used: num = ordered DATA-SPECIFIC INFORMATION
 FOR: SSR 1\. Number of variables:25 2\. Number of cases/rows: 317 3\.
 Variable List: area, year, ID, Tgu11a, Tgu11b, Calex-8a, Calex-8b,
 Pava14a, Pava14b, Tgu02a, Tgu02b, TG12-015a, TG12-015b, Pava10a, Pava10b,
 Ase50a, Ase50b, PATMP2-43a, PATMP2-43b, TG02-120a, TG02-120b, Cuu28a,
 Cuu28b, DkiB119a, DkiB119b. 4\. Missing data codes: none 5\. abbreviations
 used: none