Low food abundance prior to breeding results in female-biased sex allocation in Tengmalm’s Owl (Aegolius funerus)

Kouba, Marek; Dušek, Adam; Bartoš, Luděk; Bušina, Tomáš; Hanel, Jan; Menclová, Petra; Kouba, Petr; Popelková, Alena; Tomášek, Václav Jan; Šťastný, Karel

doi:10.1007/s10336-019-01707-1

Cited by 5 publications

(2 citation statements)

References 71 publications

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“…Further, following Hipkiss and Hörnfeldt (2004), we collected a 50 μl blood sample from each nestling by brachial vein puncture under the wing, ca. 14 days after hatching, for molecular sexing as in our previous study (Kouba et al, 2020a). Sex determination of nestlings relied on polymerase chain reaction (PCR) amplification of one intron from the sex chromosome-linked CHD1 gene, which in birds differs in size between the Z and W chromosomes (Fridolfsson and Ellegren, 1999).…”

Section: Field Proceduresmentioning

confidence: 99%

Post-fledging survival of Tengmalm’s owl offspring in boreal forests: Interactive effects of varying dynamics of main prey and habitat composition

et al. 2023

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The knowledge about the mortality rate of offspring is crucial for estimating bird population dynamics and conserving species with declining populations. Parents of predatory birds provide food for their offspring during the post-fledging dependency period, which is frequently described as essential due to inexpert flying skills. Using radio telemetry, we studied fledglings’ probability of dying by starvation and predation in Tengmalms’ owls (Aegolius funereus). Nestlings (21 and 39) from 10 and 14 broods in 2019 and 2021, respectively, were equipped with leg-mounted tags and monitored throughout the post-fledging dependency period in west-central Finland. In total, 28 out of 60 fledglings did not survive the post-fledging dependency period (12 died due to starvation, and 16 were predated). The fledglings’ probability of dying by starvation and predation was 3.7 and 2.4 times higher, respectively, in the decreasing (2019) than during the increasing (2021) abundance of main foods (voles), showing that prey availability is essential for survival during the post-fledging dependency period. The probability of starvation increased with augmenting agricultural lands in the home range and increasing precipitation after fledging, which indicated that parent owls avoided hunting in open areas and during rainy nights. The predation rate during the post-fledging dependency period increased with augmenting cover of old-growth forests in the home range. This result suggested that coverage of old-growth forests is nowadays so small in the study area that they act as ecological traps for newly-fledged owlets. The reason is that the main avian enemies of Tengmalm’s owls’ (goshawks and Ural owls) also prefer old-growth forests for breeding and hunting.

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Section: Field Proceduresmentioning

confidence: 99%

Post-fledging survival of Tengmalm’s owl offspring in boreal forests: Interactive effects of varying dynamics of main prey and habitat composition

et al. 2023

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“…Newly-hatched and half-grown nestlings of birds of prey do not usually show any sex-related physical characteristics and usually cannot be properly sexed based on body size measurements only 6 , 7 . However, identifying the sex of newly-hatched chicks holds significant importance in ecological and evolutionary studies, including, for instance, parental sex allocation 8 , 9 , sex-specific immune responses 10 , sex ratio evolution and mating systems 11 – 13 , research on the evolution of sexual size dimorphism 14 – 16 , as well as breeding and conservation management 17 – 20 .…”

Section: Introductionmentioning

confidence: 99%

Comparison of three primer pairs for molecular sex determination in Eurasian pygmy owls (Glaucidium passerinum)

Stehlíková Sovadinová,

Mekadim,

Korpimäki

et al. 2024

Sci Rep

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Bird sex determination is fundamental in various ecological and biological studies, although many avian species cannot be sexed visually due to their monomorphic and/or monochromatic appearance. Thus, reliable laboratory methods for sexing are a prerequisite. Most avian nestlings lack sex-related signs, including the Eurasian pygmy owl (Glaucidium passerinum). We performed laboratory sex determination analysis of this species using blood samples of 242 juveniles and nine adults. It relied on the qPCR of the specific intron from the chromo-helicase DNA-binding protein 1 gene. We tested three primer sets, the P2/P8, 2550F/2718R, and CHD1F/CHD1R, commonly used for bird laboratory sexing. The outcomes were displayed on an agarose gel electrophoresis and a plot from melt curve analysis, which had not been previously conducted in Eurasian pygmy owls. We found that only primer set CHD1F/CHD1R proved reliable, as the only one determined sex with one and two band/s and peak/s on the electrophoresis and the melt curve plot for males and females, respectively. The other two primer pairs failed and depicted one band/peak in all specimens regardless of their sex. Therefore, we recommend performing Eurasian pygmy owls’ laboratory sexing by qPCR with CHD1F/CHD1R primers only.

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Systematic review of avian hatching failure and implications for conservation

et al. 2023

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Avian hatching failure is a widespread phenomenon, affecting around 10% of all eggs that are laid and not lost to predation, damage, or desertion. Our understanding of hatching failure is limited in terms of both its underpinning mechanisms and its occurrence across different populations. It is widely acknowledged that rates of hatching failure are higher in threatened species and in populations maintained in captivity compared to wild, non-threatened species, but these differences have rarely been quantified and any broader patterns remain unexplored. To examine the associations between threat status, management interventions, and hatching failure across populations we conducted a phylogenetically controlled multilevel meta-analysis across 231 studies and 241 species of birds. Our data set included both threatened (Critically Endangered, Endangered, and Vulnerable) and non-threatened (Near Threatened and Least Concern) species across wild and captive populations, as well as 'wild managed' ('free-living') populations. We found the mean overall rate of hatching failure across all populations to be 16.79%, with the hatching failure rate of wild, non-threatened species being 12.40%. We found that populations of threatened species experienced significantly higher mean hatching failure than populations of non-threatened species. Different levels of management were also associated with different rates of hatching failure, with wild populations experiencing the lowest rate of hatching failure, followed by wild managed populations, and populations in captivity experiencing the highest rate. Similarly, populations that were subject to the specific management interventions of artificial incubation, supplementary feeding, and artificial nest provision displayed significantly higher rates of hatching failure than populations without these interventions. The driver of this correlation between hatching failure and management remains unclear, but could be an indirect result of threatened species being more likely to have lower hatching success and also being more likely to be subject to management, indicating that conservation efforts are fittingly being focused towards the species potentially most at risk from extinction. This is the most comprehensive comparative analysis of avian hatching failure that has been conducted to date, and the first to quantify explicitly how threat status and management are associated with the rate of hatching failure in a population. We discuss the implications of our results, focusing on their potential applications to conservation. Although we identified several factors clearly associated with variation in hatching failure, a significant amount of heterogeneity was not explained by our meta-analytical model, indicating that other factors influencing hatching failure were not included here. We discuss what these factors might be and suggest avenues for further research. Finally, we discuss the inconsistency in how hatching failure is defined and reported within the literature, and propose a stan...

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Low food abundance prior to breeding results in female-biased sex allocation in Tengmalm’s Owl (Aegolius funerus)

Cited by 5 publications

References 71 publications

Post-fledging survival of Tengmalm’s owl offspring in boreal forests: Interactive effects of varying dynamics of main prey and habitat composition

Post-fledging survival of Tengmalm’s owl offspring in boreal forests: Interactive effects of varying dynamics of main prey and habitat composition

Comparison of three primer pairs for molecular sex determination in Eurasian pygmy owls (Glaucidium passerinum)

Systematic review of avian hatching failure and implications for conservation

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