Considerable within-population variation in nest size exists among cavity nesters. We sought to e... more Considerable within-population variation in nest size exists among cavity nesters. We sought to explain this by studying a multi-brooded population of Eastern Bluebirds (Sialia sialis) breeding in nest boxes. We examined seasonal change in nest weights and compared the weights of nests built by immigrant and resident females. We further investigated whether nest weight correlated with maternal condition or breeding success. Nest weight measured after broods fledged was correlated with nest height at the start of incubation. Breeders spent fewer days building and built successively smaller, lighter nests in later nesting attempts. Female bluebirds performed the majority of nest construction. Nests built by immigrant females were significantly larger on average than those built by female recruits hatched on site, and the seasonal decline in nest weight was more pronounced for natally philopatric females. For the first time, we present evidence that the weights of philopatric females’ first nests were significantly positively correlated with the weights of the nests they were raised in, suggesting an effect of natal memory. Contrary to expectation, neither maternal condition nor reproductive success (clutch size, hatching success, brood size, and fledging success) was related to nest weight. To investigate whether smaller nests provided a thermal advantage in summer nest attempts when afternoon box temperatures can exceed 41°C, we measured the temperature within nest boxes using programmable data loggers. Mean daily maximum box temperatures during incubation were significantly positively related to nest weight and significantly negatively related to the volume of free space above the nest. Increased air circulation above the nest likely contributed to cooling the boxes when ambient temperatures were high. Reducing nest size was therefore advantageous, especially in later nesting attempts when ambient temperatures were warmest. Seasonal decline in nest weights and differences between immigrant and natally philopatric females merits further investigation.
Maternal signatures are present in the eggs of some birds, but quantifying interclutch variabilit... more Maternal signatures are present in the eggs of some birds, but quantifying interclutch variability within populations remains challenging. Maternal assignment of eggs with distinctive appearances could be used to non-invasively identify renesting females, including hens returning among years, as well as to identify cases of conspecific brood parasitism. We explored whether King Rail (Rallus elegans) eggs with shared maternity could be matched based on eggshell pattern. We used NaturePatternMatch (NPM) software to match egg images taken in the field in conjunction with spatial and temporal data on nests. Since we had only a small number of marked breeders, we analyzed similar clutch images from a study of Eurasian Common Moorhens (Gallinula chloropus chloropus) with color-banded breeders for which parentage at many nests had been verified genetically to validate the method. We ran 66 King Rail clutches (n = 338 eggs) and 58 Common Moorhen clutches (n = 364 eggs) through NPM. We perfo...
Comma-separated file with all data used for the analyses in Stiffler et al (2018). File contains ... more Comma-separated file with all data used for the analyses in Stiffler et al (2018). File contains spectrographic parameters taken from 480 Clapper Rail (CLRA) and 480 King Rail (KIRA) kek notes. The parameters of interest include Peak Frequency (Peak Freq), 1st Quartile Frequency (Q1 Freq), 3rd Quartile Frequency (Q3 Freq), Inter-quartile Range Bandwidth (IQR BW), Frequency 5% (Freq 5%), Frequency 95% (Freq 95%), and Bandwidth 90% (BW 90%). Clapper Rail vocalizations were recorded by L. Stiffler and King Rail vocalizations were recorded by K. Schroeder
ABSTRACT Female birds tend to lay consecutive eggs in a clutch 24 h apart. Typically, this spacin... more ABSTRACT Female birds tend to lay consecutive eggs in a clutch 24 h apart. Typically, this spacing results in individuals laying within a narrow interval corresponding to a time of day generalizable at the population level. In contrast to this trend, we found that females in a coastal-breeding population of King Rails (Rallus elegans) showed considerable variability in laying times. Variable laying times reveal that female King Rails are not constrained to a specific laying hour by circadian patterns of activity, as has been suggested for other species. We call for researchers to report temporal data on egg laying to revisit the evolutionary significance of laying times and to determine what factors affect, or are affected by, laying at a specific time of day.
King (Rallus elegans, KIRA) and Clapper (Rallus crepitans, CLRA) rail samples genotyped at 13 spe... more King (Rallus elegans, KIRA) and Clapper (Rallus crepitans, CLRA) rail samples genotyped at 13 species-diagnostic SNP markers. Data includes id, site number (corresponding to Figure 2), site name, and genotypes. Genotypes are identified as follows: 1=A, 2= T, 3=C, 4=G, and 0 indicates no genotype was assigned
Three strikingly different alternative male mating morphs (aggressive 'independents', sem... more Three strikingly different alternative male mating morphs (aggressive 'independents', semicooperative 'satellites' and female-mimic 'faeders') coexist as a balanced polymorphism in the ruff, Philomachus pugnax, a lek-breeding wading bird. Major differences in body size, ornamentation, and aggressive and mating behaviors are inherited as an autosomal polymorphism. We show that development into satellites and faeders is determined by a supergene consisting of divergent alternative, dominant and non-recombining haplotypes of an inversion on chromosome 11, which contains 125 predicted genes. Independents are homozygous for the ancestral sequence. One breakpoint of the inversion disrupts the essential CENP-N gene (encoding centromere protein N), and pedigree analysis confirms the lethality of homozygosity for the inversion. We describe new differences in behavior, testis size and steroid metabolism among morphs and identify polymorphic genes within the inversion t...
Considerable within-population variation in nest size exists among cavity nesters. We sought to e... more Considerable within-population variation in nest size exists among cavity nesters. We sought to explain this by studying a multi-brooded population of Eastern Bluebirds (Sialia sialis) breeding in nest boxes. We examined seasonal change in nest weights and compared the weights of nests built by immigrant and resident females. We further investigated whether nest weight correlated with maternal condition or breeding success. Nest weight measured after broods fledged was correlated with nest height at the start of incubation. Breeders spent fewer days building and built successively smaller, lighter nests in later nesting attempts. Female bluebirds performed the majority of nest construction. Nests built by immigrant females were significantly larger on average than those built by female recruits hatched on site, and the seasonal decline in nest weight was more pronounced for natally philopatric females. For the first time, we present evidence that the weights of philopatric females’ first nests were significantly positively correlated with the weights of the nests they were raised in, suggesting an effect of natal memory. Contrary to expectation, neither maternal condition nor reproductive success (clutch size, hatching success, brood size, and fledging success) was related to nest weight. To investigate whether smaller nests provided a thermal advantage in summer nest attempts when afternoon box temperatures can exceed 41°C, we measured the temperature within nest boxes using programmable data loggers. Mean daily maximum box temperatures during incubation were significantly positively related to nest weight and significantly negatively related to the volume of free space above the nest. Increased air circulation above the nest likely contributed to cooling the boxes when ambient temperatures were high. Reducing nest size was therefore advantageous, especially in later nesting attempts when ambient temperatures were warmest. Seasonal decline in nest weights and differences between immigrant and natally philopatric females merits further investigation.
Maternal signatures are present in the eggs of some birds, but quantifying interclutch variabilit... more Maternal signatures are present in the eggs of some birds, but quantifying interclutch variability within populations remains challenging. Maternal assignment of eggs with distinctive appearances could be used to non-invasively identify renesting females, including hens returning among years, as well as to identify cases of conspecific brood parasitism. We explored whether King Rail (Rallus elegans) eggs with shared maternity could be matched based on eggshell pattern. We used NaturePatternMatch (NPM) software to match egg images taken in the field in conjunction with spatial and temporal data on nests. Since we had only a small number of marked breeders, we analyzed similar clutch images from a study of Eurasian Common Moorhens (Gallinula chloropus chloropus) with color-banded breeders for which parentage at many nests had been verified genetically to validate the method. We ran 66 King Rail clutches (n = 338 eggs) and 58 Common Moorhen clutches (n = 364 eggs) through NPM. We perfo...
Comma-separated file with all data used for the analyses in Stiffler et al (2018). File contains ... more Comma-separated file with all data used for the analyses in Stiffler et al (2018). File contains spectrographic parameters taken from 480 Clapper Rail (CLRA) and 480 King Rail (KIRA) kek notes. The parameters of interest include Peak Frequency (Peak Freq), 1st Quartile Frequency (Q1 Freq), 3rd Quartile Frequency (Q3 Freq), Inter-quartile Range Bandwidth (IQR BW), Frequency 5% (Freq 5%), Frequency 95% (Freq 95%), and Bandwidth 90% (BW 90%). Clapper Rail vocalizations were recorded by L. Stiffler and King Rail vocalizations were recorded by K. Schroeder
ABSTRACT Female birds tend to lay consecutive eggs in a clutch 24 h apart. Typically, this spacin... more ABSTRACT Female birds tend to lay consecutive eggs in a clutch 24 h apart. Typically, this spacing results in individuals laying within a narrow interval corresponding to a time of day generalizable at the population level. In contrast to this trend, we found that females in a coastal-breeding population of King Rails (Rallus elegans) showed considerable variability in laying times. Variable laying times reveal that female King Rails are not constrained to a specific laying hour by circadian patterns of activity, as has been suggested for other species. We call for researchers to report temporal data on egg laying to revisit the evolutionary significance of laying times and to determine what factors affect, or are affected by, laying at a specific time of day.
King (Rallus elegans, KIRA) and Clapper (Rallus crepitans, CLRA) rail samples genotyped at 13 spe... more King (Rallus elegans, KIRA) and Clapper (Rallus crepitans, CLRA) rail samples genotyped at 13 species-diagnostic SNP markers. Data includes id, site number (corresponding to Figure 2), site name, and genotypes. Genotypes are identified as follows: 1=A, 2= T, 3=C, 4=G, and 0 indicates no genotype was assigned
Three strikingly different alternative male mating morphs (aggressive 'independents', sem... more Three strikingly different alternative male mating morphs (aggressive 'independents', semicooperative 'satellites' and female-mimic 'faeders') coexist as a balanced polymorphism in the ruff, Philomachus pugnax, a lek-breeding wading bird. Major differences in body size, ornamentation, and aggressive and mating behaviors are inherited as an autosomal polymorphism. We show that development into satellites and faeders is determined by a supergene consisting of divergent alternative, dominant and non-recombining haplotypes of an inversion on chromosome 11, which contains 125 predicted genes. Independents are homozygous for the ancestral sequence. One breakpoint of the inversion disrupts the essential CENP-N gene (encoding centromere protein N), and pedigree analysis confirms the lethality of homozygosity for the inversion. We describe new differences in behavior, testis size and steroid metabolism among morphs and identify polymorphic genes within the inversion t...
Uploads