Apparent survival, territory turnover and site fidelity rates in Northern Goshawk Accipiter gentilis populations close to the northern range limit

Capsule: Mark-recapture data suggest low apparent survival and sex- and population-specific site fidelity and territory turnover in adult Northern Goshawks Accipiter gentilis breeding in northern Europe.Aims: To understand how species cope with global environmental change requires knowledge of variation in population demographic rates, especially from populations close to the species' northern range limit and from keystone species such as raptors. We analyse apparent survival and breeding dispersal propensity of adult Northern Goshawks breeding in northern Europe.Methods: We used long-term mark-recapture data from two populations in Finland, northern Europe, and Cormack-Jolly-Seber models and binomial generalized linear models to investigate sex- and population-specific variation in apparent survival, territory turnover and site fidelity.Results: We report low apparent survival (53-72%) of breeding adult Goshawks. Breeding dispersal propensity was higher in females than males, especially in northern Finland, contrasting with previous studies that suggest high site fidelity in both sexes.Conclusion: Low apparent survival in females may be mainly due to permanent emigration outside the study areas, whereas in males the survival rate may truly be low. Both demographic aspects may be driven by the combination of sex-specific roles related to breeding and difficult environmental conditions prevailing in northern latitudes during the non-breeding season.Peer reviewe

Information collected during the post-breeding season guides future breeding decisions in a migratory bird

Breeding habitat choice and investment decisions are key contributors to fitness in animals. Density of individuals is a well-known cue of habitat quality used for future breeding decisions, but accuracy of density cues decreases as individuals disperse from breeding sites. Used nests remain an available information source also after breeding season, but whether such information is used for breeding decisions is less well known. We experimentally investigated whether migratory, cavity-nesting pied flycatchers (Ficedula hypoleuca) prospect potential breeding sites after breeding season and use old nests as a cue for future breeding decisions. In late summer 2013, forest sites were assigned to four treatments: (1) sites including nest boxes with old nests of heterospecifics (tits), (2) sites including suitable but empty nest boxes, (3) sites with unsuitable nest boxes, or (4) sites without any nest boxes. In the following year, we investigated pied flycatcher habitat choice and reproductive investment according to these "past" cues while also controlling for additional information sources present during settlement. Flycatchers preferred sites where tits had been perceived to breed in the previous year, but only if great tits were also currently breeding in the site and had a relatively high number of eggs. Old flycatchers avoided sites previously treated with suitable but empty cavities, whereas young flycatchers preferred sites where tits had apparently bred in the previous year. Also egg mass, but not clutch size or clutch mass, was affected by the combination of past treatment information and current tit abundance

Interspecific information on predation risk affects nest site choice in a passerine bird

Abstract Background Breeding site choice constitutes an important part of the species niche. Nest predation affects breeding site choice, and has been suggested to drive niche segregation and local coexistence of species. Interspecific social information use may, in turn, result in copying or rejection of heterospecific niche characteristics and thus affect realized niche overlap between species. We tested experimentally whether a migratory bird, the pied flycatcher Ficedula hypoleuca, collects information about nest predation risk from indirect cues of predators visiting nests of heterospecific birds. Furthermore, we investigated whether the migratory birds can associate such information with a specific nest site characteristic and generalize the information to their own nest site choice. Results Our results demonstrate that flycatchers can use the fate of heterospecific nesting attempts in their own nest site choice, but do so selectively. Young flycatcher females, when making the decision quickly, associated the fate of an artificial nest with nest-site characteristics and avoided the characteristic associated with higher nest predation risk. Conclusions Copying nest site choices of successful heterospecifics, and avoiding choices which led to failed attempts, may amplify or counter effects of nest predation on niche overlap, with important consequences for between-species niche divergence-convergence dynamics, species coexistence and predator-prey interactions

Interspecific information on predation risk affects nest site choice in a passerine bird

BackgroundBreeding site choice constitutes an important part of the species niche. Nest predation affects breeding site choice, and has been suggested to drive niche segregation and local coexistence of species. Interspecific social information use may, in turn, result in copying or rejection of heterospecific niche characteristics and thus affect realized niche overlap between species. We tested experimentally whether a migratory bird, the pied flycatcher Ficedula hypoleuca, collects information about nest predation risk from indirect cues of predators visiting nests of heterospecific birds. Furthermore, we investigated whether the migratory birds can associate such information with a specific nest site characteristic and generalize the information to their own nest site choice.ResultsOur results demonstrate that flycatchers can use the fate of heterospecific nesting attempts in their own nest site choice, but do so selectively. Young flycatcher females, when making the decision quickly, associated the fate of an artificial nest with nest-site characteristics and avoided the characteristic associated with higher nest predation risk.ConclusionsCopying nest site choices of successful heterospecifics, and avoiding choices which led to failed attempts, may amplify or counter effects of nest predation on niche overlap, with important consequences for between-species niche divergence-convergence dynamics, species coexistence and predator-prey interactions.</div

Do large-scale associations in birds imply biotic interactions or environmental filtering?

Aim There has been a wide interest in the effect of biotic interactions on species' occurrences and abundances at large spatial scales, coupled with a vast development of the statistical methods to study them. Still, evidence for whether the effects of within-trophic-level biotic interactions (e.g. competition and heterospecific attraction) are discernible beyond local scales remains inconsistent. Here, we present a novel hypothesis-testing framework based on joint dynamic species distribution models and functional trait similarity to dissect between environmental filtering and biotic interactions. Location France and Finland. Taxon Birds. Methods We estimated species-to-species associations within a trophic level, independent of the main environmental variables (mean temperature and total precipitation) for common species at large spatial scale with joint dynamic species distribution (a multivariate spatiotemporal delta model) models. We created hypotheses based on species' functionality (morphological and/or diet dissimilarity) and habitat preferences about the sign and strength of the pairwise spatiotemporal associations to estimate the extent to which they result from biotic interactions (competition, heterospecific attraction) and/or environmental filtering. Results Spatiotemporal associations were mostly positive (80%), followed by random (15%), and only 5% were negative. Where detected, negative spatiotemporal associations in different communities were due to a few species. The relationship between spatiotemporal association and functional dissimilarity among species was negative, which fulfils the predictions of both environmental filtering and heterospecific attraction. Main conclusions We showed that processes leading to species aggregation (mixture between environmental filtering and heterospecific attraction) seem to dominate assembly rules, and we did not find evidence for competition. Altogether, our hypothesis-testing framework based on joint dynamic species distribution models and functional trait similarity is beneficial in ecological interpretation of species-to-species associations from data covering several decades and biogeographical regions.Peer reviewe

First-Time Migration in Juvenile Common Cuckoos Documented by Satellite Tracking

Being an obligate parasite, juvenile common cuckoos Cuculus canorus are thought to reachtheir African wintering grounds from Palearctic breeding grounds without guidance fromexperienced conspecifics but this has not been documented. We used satellite tracking tostudy naïve migrating common cuckoos. Juvenile cuckoos left breeding sites in Finlandmoving slowly and less consistently directed than adult cuckoos. Migration of the juveniles(N = 5) was initiated later than adults (N = 20), was directed toward the southwest±significantlydifferent from the initial southeast direction of adults±and included strikingly long BalticSea crossings (N = 3). After initial migration of juvenile cuckoos toward Poland, themigration direction changed and proceeded due south, directly toward the winter grounds,as revealed by a single tag transmitting until arrival in Northwest Angola where northernadult cuckoos regularly winter. Compared to adults, the juvenile travelled straighter andfaster, potentially correcting for wind drift along the route. That both migration route and timingdiffered from adults indicates that juvenile cuckoos are able to reach proper winteringgrounds independently, guided only by their innate migration programme.</p

Maternally transferred thyroid hormones and life-history variation in birds

1. In vertebrates, thyroid hormones (THs) play an important role in the regulation of growth, development, metabolism, photoperiodic responses and migration. Maternally transferred THs are important for normal early phase embryonic development when embryos are not able to produce endogenous THs. Previous studies have shown that variation in maternal THs within the physiological range can influence offspring phenotype. 2. Given the essential functions of maternal THs in development and metabolism, THs may be a mediator of life-history variation across species. 3. We tested the hypothesis that differences in life histories are associated with differences in maternal TH transfer across species. Using birds as a model, we specifically tested whether maternally transferred yolk THs covary with migratory status, developmental mode and traits related to pace-of-life (e.g. basal metabolic rate, maximum life span). 4. We collected un-incubated eggs (n = 1-21 eggs per species, median = 7) from 34 wild and captive bird species across 17 families and six orders to measure yolk THs [both triiodothyronine (T3) and thyroxine (T4)], compiled life-history trait data from the literature and used Bayesian phylogenetic mixed models to test our hypotheses. 5. Our models indicated that both concentrations and total amounts of the two main forms of THs (T3 and T4) were higher in the eggs of migratory species compared to resident species, and total amounts were higher in the eggs of precocial species, which have longer prenatal developmental periods, than in those of altricial species. However, maternal yolk THs did not show clear associations with pace-of-life-related traits, such as fecundity, basal metabolic rate or maximum life span. 6. We quantified interspecific variation in maternal yolk THs in birds, and our findings suggest higher maternal TH transfer is associated with the precocial mode of development and migratory status. Whether maternal THs represent a part of the mechanism underlying the evolution of precocial development and migration or a consequence of such life histories is currently unclear. We therefore encourage further studies to explore the physiological mechanisms and evolutionary processes underlying these patterns.</p

Maternally‐transferred thyroid hormones and life‐history variation in birds

This is the final version. Available on open access from Wiley via the DOI in this recordThe data and the R code used to produce the results of this study are available from the Dryad Digital Repository: https://doi.org/10.5061/dryad.547d7wmb5.1. In vertebrates, thyroid hormones (THs) play an important role in the regulation of growth, development, metabolism, photoperiodic responses and migration. Maternally transferred THs are important for normal early-phase embryonic development when embryos are not able to produce endogenous THs. Previous studies have shown that variation in maternal THs within the physiological range can influence offspring phenotype. 2. Given the essential functions of maternal THs in development and metabolism, THs may be a mediator of life-history variation across species. 3. We tested the hypothesis that differences in life histories are associated with differences in maternal TH transfer across species. Using birds as a model, we specifically tested whether maternally transferred yolk THs co-vary with migratory status, developmental mode, and traits related to pace-of-life (e.g. basal metabolic rate, maximum lifespan). 4. We collected un-incubated eggs (n = 1-21 eggs per species, median = 7) from 34 wild and captive bird species across 17 families and 6 orders to measure yolk THs (both triiodothyronine, T3 and thyroxine, T4), compiled life-history trait data from the literature, and used Bayesian phylogenetic mixed models to test our hypotheses. 5. Our models indicated that both concentrations and total amounts of the two main forms of THs (T3 and T4) were higher in the eggs of migratory species compared to resident species, and total amounts were higher in the eggs of precocial species, which have longer prenatal developmental periods, than in those of altricial species. However, maternal yolk THs did not show clear associations with pace-of-life related traits, such as fecundity, basal metabolic rate, or maximum lifespan. 6. We quantified interspecific variation in maternal yolk THs in birds and our findings suggest higher maternal TH transfer is associated with the precocial mode of development and migratory status. Whether maternal THs represent a part of the mechanism underlying the evolution of precocial development and migration or a consequence of such life histories is currently unclear. We therefore encourage further studies to explore the physiological mechanisms and evolutionary processes underlying these patterns.Academy of FinlandAcademy of FinlandCape Horn International Center, Chil

The effect of climate change on avian offspring production: A global meta-analysis

Climate change affects timing of reproduction in many bird species, but few studies have investigated its influence on annual reproductive output. Here, we assess changes in the annual production of young by female breeders in 201 populations of 104 bird species (N = 745,962 clutches) covering all continents between 1970 and 2019. Overall, average offspring production has declined in recent decades, but considerable differences were found among species and populations. A total of 56.7% of populations showed a declining trend in offspring production (significant in 17.4%), whereas 43.3% exhibited an increase (significant in 10.4%). The results show that climatic changes affect offspring production through compounded effects on ecological and life history traits of species. Migratory and larger-bodied species experienced reduced offspring production with increasing temperatures during the chick-rearing period, whereas smaller-bodied, sedentary species tended to produce more offspring. Likewise, multi-brooded species showed increased breeding success with increasing temperatures, whereas rising temperatures were unrelated to repro- ductive success in single-brooded species. Our study suggests that rapid declines in size of bird populations reported by many studies from different parts of the world are driven only to a small degree by changes in the production of young

Informed habitat choice in the heterogeneous world: ecological implications and evolutionary potential

Abstract Animals live in a heterogeneous world where threats and abundance and quality of resources vary across space and time. Heterogeneity induces uncertainty in decisions that animals must make, e.g., where to breed. Adaptive decisions may be facilitated by personally collecting information on the quality of the environment and by observing the behaviour and success of other individuals. Such social information use is common in nature. I investigate information use in relation to ecological threats (brood parasites, nest predators) and long-term information use in breeding site choice in the wild. Moreover, I examine the genetic basis of social cue use in breeding site choice. I demonstrated experimentally that open-nesting hosts of a brood parasite, the common cuckoo (Cuculus canorus), can cue on cuckoo vocalizations to estimate cuckoo abundance and avoid breeding sites with high perceived parasitism risk. Another experiment showed that pied flycatchers (Ficedula hypoleuca) derive predation risk information from the fates of heterospecific nests, can associate the information with a nest site characteristic and generalize the association to own nest site choice. However, apparently only young females that made their choice quickly used the information in nest site choice. Pied flycatchers were further observed to collect habitat quality information based on the old nest contents during the post-breeding period. Use of the information in breeding site choice in the following spring varied between sex and age groups as well as geographically. Some birds integrated the post-breeding period information with the information available during settlement suggesting sequential social information use. Finally, quantitative genetic analyses revealed low additive genetic variances and genetic heritabilities of social cue use in breeding site choice in a collared flycatcher (Ficedula albicollis) population. These results demonstrate new aspects of informed habitat choice in wild animals which have important implications for species coexistence and community ecology, parasite-host coevolution, between-species niche dynamics and evolution. Between-individual variation in information use is highlighted throughout the thesis and warrants further research. The evolutionary potential of information use appears low, but more studies in other populations and species are needed.Tiivistelmä Eläimet elävät ympäristössä, jossa resurssit ja uhat vaihtelevat ajallisesti ja alueellisesti. Tämä vaihtelu aiheuttaa epävarmuutta eläinten päätöksentekoon, kuten pesimäpaikan valintaan. Hyödyllisten päätösten tekoa voi edesauttaa keräämällä tietoa ympäristön laadusta itsenäisesti tai seuraamalla muiden yksilöiden käytöstä ja menestystä. Tällainen sosiaalisen informaation käyttö on yleistä eläinkunnassa. Tutkin informaation käyttöä ekologisten uhkien (pesäloiset, -pedot) suhteen ja pitkäaikaista informaation käyttöä pesimäpaikan valinnassa luonnonpopulaatioissa. Lisäksi selvitän pesimäpaikan valintaan liittyvän informaation käyton geneettistä periytyvyyttä. Selvitin kokeellisesti, että pesäloisen, käen (Cuculus canorus), isäntälajit voivat käyttää käkien ääntelyä vihjeenä alueellisesta loisintauhasta ja siten välttää korkean uhan alueita pesimäpaikan valinnassa. Toisessa kokeessa havaittiin kirjosieppojen (Ficedula hypoleuca) keräävän tietoa pesäpetouhasta toisen lajin pesätuhojen kautta, kykenevän yhdistämään tiedon erilliseen pesäpaikan ominaisuuteen ja käyttämään tätä assosiaatiota omassa pesäpaikan valinnassa. Kuitenkin vain nuoret naaraat, jotka tekivät valintansa nopeasti, käyttivät kyseistä informaatiota valinnassaan. Lisäksi havaitsin kirjosieppojen keräävän tietoa ympäristön laadusta pesinnän jälkeen vanhojen pesäsisältöjen avulla. Kyseisen tiedon käyttö pesimäpaikan valinnassa seuraavana keväänä vaihteli lintujen sukupuolen ja iän suhteen, kuin myös alueellisesti. Osa linnuista yhdisti pesimäpaikan valinnassaan aikaisempaa, pesinnän jälkeen kerättyä tietoa ja keväällä saatavilla olevaa sosiaalista informaatiota. Geneettinen analyysi viittasi pesimäpaikan valintaan liittyvän informaation käytön alhaiseen additiivisen geneettisen varianssin määrään ja siten alhaiseen geneettiseen periytyvyyteen sepelsiepolla (Ficedula albicollis). Väitöskirjani tulokset kuvaavat uudenlaisia informaation käytön muotoja eläinten pesimäpaikan valinnassa. Havainnot auttavat ymmärtämään pesälois-isäntä rinnakkaisevoluutiota, lajien välisiä vuorovaikutuksia, lajiyhteisöjen toimintaa ja evoluutiota. Yksilöiden välinen vaihtelu informaation käytössä näyttää olevan yleistä, ja lisätutkimuksen tarpeessa. Informaation käytön evolutiivinen potentiaali näyttää rajalliselta, mutta lisätutkimukset eri populaatioilla ja lajeilla ovat tarpeen