scholarly journals Interactive influences of fluctuations of main food resources and climate change on long-term population decline of Tengmalm’s owls in the boreal forest

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Marek Kouba ◽  
Luděk Bartoš ◽  
Jitka Bartošová ◽  
Kari Hongisto ◽  
Erkki Korpimäki
Keyword(s):  
Climate Change ◽  
Reproductive Success ◽  
Population Decline ◽  
Egg Laying ◽  
Laying Date ◽  
Late Winter ◽  
Aegolius Funereus ◽  
Increasing Temperature ◽  
Tengmalm's Owl

AbstractRecent wildlife population declines are usually attributed to multiple sources such as global climate change and habitat loss and degradation inducing decreased food supply. However, interactive effects of fluctuations in abundance of main foods and weather conditions on population densities and reproductive success have been studied rarely. We analysed long-term (1973–2018) data on Tengmalm’s owl (Aegolius funereus) and the influence of prey abundance and weather on breeding densities and reproductive success in western Finland. We found that fledgling production per breeding attempt declined and laying date of the owl population delayed during the period between 1973 and 2018. The breeding density of the owl population decreased with increasing temperature in winter (October–March), fledgling production increased with increasing temperature and precipitation in spring (April–June), whereas the initiation of egg-laying was delayed with increasing depth of snow cover in late winter (January–March). The decreasing trend of fledgling production, which was mainly due to starvation of offspring, was an important factor contributing to the long-term decline of the Tengmalm’s owl study population. Milder and more humid spring and early summer temperatures due to global warming were not able to compensate for lowered offspring production of owls. The main reason for low productivity is probably loss and degradation of mature and old-growth forests due to clear-felling which results in loss of coverage of prime habitat for main (bank voles) and alternative foods (small birds) of owls inducing lack of food, and refuges against predators of Tengmalm’s owls. This interpretation was also supported by the delayed start of egg-laying during the study period although ambient temperatures increased prior to and during the egg-laying period.

scholarly journals Long-term trends in the body condition of parents and offspring of Tengmalm’s owls under fluctuating food conditions and climate change

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Marek Kouba ◽  
Luděk Bartoš ◽  
Jitka Bartošová ◽  
Kari Hongisto ◽  
Erkki Korpimäki
Keyword(s):  
Climate Change ◽  
Snow Cover ◽  
Body Condition ◽  
The Body ◽  
Adult Survival ◽  
Late Winter ◽  
Study Population ◽  
Males And Females ◽  
Tengmalm's Owl

AbstractPhysical condition is important for the ability to resist various parasites and diseases as well as in escaping predators thus contributing to reproductive success, over-winter survival and possible declines in wildlife populations. However, in-depth research on trends in body condition is rare because decades-long datasets are not available for a majority of species. We analysed the long-term dataset of offspring covering 34 years, male parents (40 years) and female parents (42 years) to find out whether the decline of Tengmalm’s owl population in western Finland is attributable to either decreased adult and/or juvenile body condition in interaction with changing weather conditions and density estimates of main foods. We found that body condition of parent owl males and females declined throughout the 40-year study period whereas the body condition of owlets at the fledging stage very slightly increased. The body condition of parent owls increased with augmenting depth of snow cover in late winter (January to March), and that of offspring improved with increasing precipitation in late spring (May to June). We conclude that the decreasing trend of body condition of parent owl males and females is important factor probably inducing reduced adult survival and reduced reproduction success thus contributing to the long-term decline of the Tengmalm’s owl study population. The very slightly increasing trend of body condition of offspring is obviously not able to compensate the overall decline of Tengmalm’s owl population, because the number of offspring in turn simultaneously decreased considerably in the long-term. The ongoing climate change appeared to work in opposite ways in this case because declining depth of snow cover will make the situation worse but increased precipitation will improve. We suggest that the main reasons for long-term decline of body condition of parent owls are interactive or additive effects of reduced food resources and increased overall predation risk due to habitat degradation (loss and fragmentation of mature and old-growth forests due to clear-felling) subsequently leading to decline of Tengmalm’s owl study population.

scholarly journals Breeding Phenology of Red-Shouldered Hawks (Buteo lineatus) Is Related to Snow Cover and Air Temperature During the Pre-Laying Period

2021 ◽  
Vol 9 ◽  
Author(s):  
Cheryl R. Dykstra ◽  
Jeffrey L. Hays ◽  
Melinda M. Simon ◽  
Ann R. Wegman
Keyword(s):  
Climate Change ◽  
Snow Cover ◽  
Air Temperature ◽  
Global Climate ◽  
Weather Conditions ◽  
Egg Laying ◽  
Laying Date ◽  
Hatching Date ◽  
Breeding Phenology

Global climate change has advanced the breeding phenology of many avian species. However, raptors’ breeding phenologies may not respond in the same way to the factors that influence passerine breeding dates. We studied reproduction of suburban and rural Red-shouldered Hawks (Buteo lineatus) in southern Ohio, United States, from 1997 to 2020. Mean hatching dates for 786 broods were 24 April [Julian day: 114.1 ± 0.3 d (SE)] for suburban birds and 25 April (Julian day: 114.5 ± 0.4) for rural birds. Egg-laying date averages approximately 33 days before hatching date, or about the third week of March. We used mixed models to test which factors influenced nestling hatching dates from 1997 to 2020. The best model included year, days of snow cover during the pre-laying period (February–March), and mean March temperature, with days of snow cover having the largest effect. Hatching date (in Julian days) was positively related to snow cover and negatively related to air temperature, i.e., young hatched earlier in years with fewer days of snow cover and in warmer years). Young also hatched slightly later as the study progressed. Overall, neither mean hatching date nor any of the weather variables showed a significant trend over the course of the study. Previously published reports indicate that many raptor species do not exhibit advancing hatching dates, and breeding phenologies often reflect local weather conditions. The complexity and diversity of raptor responses to climate change underscore the importance of long-term studies of raptors at multiple locations.

Changes in timing of breeding and reproductive success in birds

2019 ◽  
pp. 108-119 ◽  
Author(s):  
Peter O. Dunn
Keyword(s):  
Climate Change ◽  
Food Intake ◽  
Reproductive Success ◽  
Egg Laying ◽  
Laying Date ◽  
Timing Of Breeding ◽  
Potential Threat ◽  
Daily Food Intake ◽  
Bird Populations ◽  
Daily Food

Many studies on birds have shown advancing dates of egg-laying in response to climate change. This chapter reviews the latest knowledge about the roles of photoperiod, food abundance, body condition, and hormones in regulating the timing of egg-laying. A variety of responses and predictors have been discovered in recent studies, some of which may be related to whether a species relies on daily food intake (‘income’) or stored resources (‘capital’) for breeding. The literature on advancing laying dates shows that the rate is dependent on the number of broods per season, habitat, and trophic level. Mismatches between timing of breeding and peaks in food supply are often mentioned as a potential threat to populations. However, to date, there is no association between changes in laying date and population trends, which suggests that the effects of climate change on bird populations may be driven by other factors.

scholarly journals Birds advancing lay dates with warming springs face greater risk of chick mortality

2020 ◽  
Vol 117 (41) ◽  
pp. 25590-25594 ◽  
Author(s):  
J. Ryan Shipley ◽  
Cornelia W. Twining ◽  
Conor C. Taff ◽  
Maren N. Vitousek ◽  
Andrea Flack ◽  
...  
Keyword(s):  
Climate Change ◽  
Reproductive Success ◽  
Egg Laying ◽  
Tree Swallow ◽  
Population Declines ◽  
Chick Survival ◽  
Ambient Temperatures ◽  
Inclement Weather ◽  
Aerial Insectivores

In response to a warming planet with earlier springs, migratory animals are adjusting the timing of essential life stages. Although these adjustments may be essential for keeping pace with resource phenology, they may prove insufficient, as evidenced by population declines in many species. However, even when species can match the tempo of climate change, other consequences may emerge when exposed to novel conditions earlier in the year. Here, using three long-term datasets on bird reproduction, daily insect availability, and weather, we investigated the complex mechanisms affecting reproductive success in an aerial insectivore, the tree swallow (Tachycineta bicolor). By examining breeding records over nearly half a century, we discovered that tree swallows have continuously advanced their egg laying by ∼3 d per decade. However, earlier-hatching offspring are now exposed to inclement weather events twice as often as they were in the 1970s. Our long-term daily insect biomass dataset shows no long-term trends over 25 y but precipitous drops in flying insect numbers on days with low ambient temperatures. Insect availability has a considerable impact on chick survival: Even a single inclement weather event can reduce offspring survival by >50%. Our results highlight the multifaceted threats that climate change poses on migrating species. The decoupling between cold snap occurrence and generally warming spring temperatures can affect reproductive success and threaten long-term persistence of populations. Understanding the exact mechanisms that endanger aerial insectivores is especially timely because this guild is experiencing the steepest and most widespread declines across North America and Europe.

Laying date of marsh tits Parus palustris in relation to climate change

Biologia ◽  
2006 ◽  
Vol 61 (5) ◽  
Author(s):  
Zdravko Dolenec
Keyword(s):  
Climate Change ◽  
Life History Traits ◽  
Laying Date ◽  
Bird Breeding ◽  
Spring Temperatures ◽  
The Mean ◽  
The Relationship ◽  
Marsh Tit ◽  
Term Data

AbstractIncreasing evidence suggests that climate change affects bird breeding phenology and other life-history traits of wildlife. This study is based on the mean spring temperatures (February, March, April) and laying dates of first eggs of the marsh tit Parus palustris. We collected data from 1984 to 2004 for the Mokrice area in NW Croatia. Correlation between laying date and mean spring temperatures was significant. The relationship between mean laying date (y) and air temperature (x) can be expressed as y = 44.69 − 2.08x. Results indicate that spring temperatures are a good predictor of timing of laying eggs. Such long-term data could than be used in order to assess the effects on biological systems if human activities influence climate.

scholarly journals Long-term monitoring at multiple trophic levels suggests heterogeneity in responses to climate change in the Canadian Arctic tundra

2013 ◽  
Vol 368 (1624) ◽  
pp. 20120482 ◽  
Author(s):  
Gilles Gauthier ◽  
Joël Bêty ◽  
Marie-Christine Cadieux ◽  
Pierre Legagneux ◽  
Madeleine Doiron ◽  
...  
Keyword(s):  
Climate Change ◽  
Primary Production ◽  
Climate Warming ◽  
Temporal Trends ◽  
Canadian Arctic ◽  
Trophic Levels ◽  
Food Plants ◽  
Laying Date ◽  
Snow Melt

Arctic wildlife is often presented as being highly at risk in the face of current climate warming. We use the long-term (up to 24 years) monitoring records available on Bylot Island in the Canadian Arctic to examine temporal trends in population attributes of several terrestrial vertebrates and in primary production. Despite a warming trend (e.g. cumulative annual thawing degree-days increased by 37% and snow-melt date advanced by 4–7 days over a 23-year period), we found little evidence for changes in the phenology, abundance or productivity of several vertebrate species (snow goose, foxes, lemmings, avian predators and one passerine). Only primary production showed a response to warming (annual above-ground biomass of wetland graminoids increased by 123% during this period). We nonetheless found evidence for potential mismatches between herbivores and their food plants in response to warming as snow geese adjusted their laying date by only 3.8 days on average for a change in snow-melt of 10 days, half of the corresponding adjustment shown by the timing of plant growth (7.1 days). We discuss several reasons (duration of time series, large annual variability, amplitude of observed climate change, nonlinear dynamic or constraints imposed by various rate of warming with latitude in migrants) to explain the lack of response by herbivores and predators to climate warming at our study site. We also show how length and intensity of monitoring could affect our ability to detect temporal trends and provide recommendations for future monitoring.

scholarly journals Climate change and the risks associated with delayed breeding in a tropical wild bird population

2011 ◽  
Vol 278 (1722) ◽  
pp. 3184-3190 ◽  
Author(s):  
Deepa Senapathi ◽  
Malcolm A. C. Nicoll ◽  
Celine Teplitsky ◽  
Carl G. Jones ◽  
Ken Norris
Keyword(s):  
Climate Change ◽  
Wild Bird ◽  
Population Decline ◽  
Biodiversity Loss ◽  
Climatic Conditions ◽  
Timing Of Breeding ◽  
Wild Populations ◽  
Bird Population ◽  
Island Endemic

There is growing evidence of changes in the timing of important ecological events, such as flowering in plants and reproduction in animals, in response to climate change, with implications for population decline and biodiversity loss. Recent work has shown that the timing of breeding in wild birds is changing in response to climate change partly because individuals are remarkably flexible in their timing of breeding. Despite this work, our understanding of these processes in wild populations remains very limited and biased towards species from temperate regions. Here, we report the response to changing climate in a tropical wild bird population using a long-term dataset on a formerly critically endangered island endemic, the Mauritius kestrel. We show that the frequency of spring rainfall affects the timing of breeding, with birds breeding later in wetter springs. Delays in breeding have consequences in terms of reduced reproductive success as birds get exposed to risks associated with adverse climatic conditions later on in the breeding season, which reduce nesting success. These results, combined with the fact that frequency of spring rainfall has increased by about 60 per cent in our study area since 1962, imply that climate change is exposing birds to the stochastic risks of late reproduction by causing them to start breeding relatively late in the season.

Divorce and breeding dispersal in the dunlin Calidris alpina: support for the better option hypothesis?

Behaviour ◽  
2012 ◽  
Vol 149 (1) ◽  
pp. 67-80 ◽  
Author(s):  
Donald Blomqvist ◽  
Lars-Åke Flodin
Keyword(s):  
Reproductive Success ◽  
Egg Laying ◽  
Male Reproductive Success ◽  
Breeding Dispersal ◽  
Social Monogamy ◽  
Calidris Alpina ◽  
Pair Bonds ◽  
Mate Change ◽  
Term Data

AbstractSocial monogamy is a rare mating system among animals, occurring commonly only in birds. In long-lived birds, pair bonds may persist for several seasons in some species, while in others mate change occurs even when both partners are still alive. Here, we test predictions from the adaptive hypotheses for divorce, using long-term data (15 years) on mate change and reproductive success in a long-lived shorebird, the dunlin Calidris alpina. We found that about one quarter of the pairs divorced (23% of 126 breeding attempts). Among the divorcing females, six changed partner more than once (one female changed partner three times). Following divorce, females dispersed longer than males. Start of egg-laying (presumably reflecting arrival time to the breeding ground), previous breeding success, and male age or size did not seem to influence the occurrence of divorce. However, females that changed mate between consecutive breeding attempts achieved higher reproductive success. Moreover, this improvement appeared independent of breeding experience. Since we were unable to detect any effect of divorce on male reproductive success, our results suggest that divorce in the dunlin is best explained by the better option hypothesis.

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