Spring Arrival Research Articles

Sharp Differences in the Timing of Male and Female Spring Arrival in the European Stonechat, Saxicola Rubicola, and the Whinchat, S. Rubetra (Passeriformes, Muscicapidae), in North-Eastern Ukraine

Abstract Protandry, or the arrival of males prior to females to the breeding grounds is a widespread phenomenon in migratory birds though rarely examined in related species in which its manifestation can vary. European Stonechat and Whinchat are such a pair studied with use of individual marking in North-Eastern Ukraine in 1993–2008. An apparent protandry was found in Whinchat but not in European Stonechat. The difference between the arrival dates of male and female Whinchats (6 days) was significant. The mean time span between territory establishment by a male and subsequent pair formation was 10.6 days. By contrast, 38% of the first records of European Stonechats in spring were those of already paired birds and the difference between arrival dates of both sexes was non-significant. The proximate cause of protandry in Whinchat and its’ absence in European Stonechat seems to be the differences (or the lack thereof) in the onset of spring migration. The time lapse between the start of migration of male and female Whinchats originates at African wintering grounds and is maintained en route. The absence of the protandry in European Stonechat is probably a relict behaviour from the residency. The protandry in migratory populations of this species is yet to be developed.

Idiosyncratic changes in spring arrival dates of Pacific Northwest migratory birds.

Shifts in the timing of bird migration have been associated with climatic change and species traits. However, climatic change does not affect all species or geographic locations equally. Climate in the Pacific Northwest has shifted during the last century with mean temperatures increasing by 1 °C but little change in total annual precipitation. Few long-term data on migration phenology of birds are available in the Pacific Northwest. We analyzed trends in spring arrival dates from a site in the Oregon Coast Range where nearly daily inventories of birds were conducted in 24 of 29 years. Several species showed statistically significant shifts in timing of first spring arrivals. Six of 18 species occur significantly earlier now than during the initial phase of the study. One species arrives significantly later. Eleven show no significant shifts in timing. We associated trends in spring migration phenology with regional climatic variables, weather (precipitation and temperature), traits of species such as migration strategy, foraging behavior, diet, and habitat use, and regional trends in abundance as indexed by Breeding Bird Survey data. We found no set of variables consistently correlated with avian phenological changes. Post hoc analyses of additional climate variables revealed an association of migratory arrival dates across the 18 species with rainfall totals in northern California, presumably indicating that songbird arrival dates in Oregon are slowed by spring storm systems in California. When only the six species with the most strongly advancing arrival dates were analyzed, winter maximum temperatures in the preceding three winters appeared consistently in top models, suggesting a possible role for food availability early in spring to promote the survival and successful reproduction of the earliest-arriving birds. However, additional data on food availability and avian survival and reproductive success are required to test that hypothesis. Despite the appearance of some climate variables in top models, there remains a mismatch between strongly advancing arrival dates in some songbirds and a lack of clear directional change in those climate variables. We conclude that either some previously unrecognized variable or combination of variables has affected the timing of migration in some species but not others, or the appearance of statistically significant directional changes over time can occur without being driven by consistent environmental or species-specific factors.

Non-structural Carbohydrates in Dormant Woody Perennials; The Tale of Winter Survival and Spring Arrival

Woody perennials’ reliance on nonstructural carbohydrates (NSC) reserves for the resumption of spring growth necessitates an accumulation of NSC prior to dormancy. It is assumed that during dormancy temperature-regulated biological activities gauge the progression of winter and affect the metabolic rates and physiology of NSC reserves. Thus, changes in temperature signal the arrival of spring and determine the amount of reserves available for growth resumption. As woody perennials are dependent on dispersed storage of NSC during spring, they need an integrated remobilization and redistribution for synchronous and effective development of photosynthetic and reproductive organs. However, it is not known how storage compartments interact at the whole plant level, when NSC reserves are mobilized, or how local and distal storage compartments influence the biology of spring growth resumption. The goal of this mini-review is to shift the focus of winter biology from bud-centric to the whole plant. We discuss winter NSC management in the context of climate change with a special emphasis on how projected mild winters may affect the carbon budget, transport, and allocation during winter. We look at three aspects of NSC regulation underlying dormancy (I) the molecular regulation of dormancy (II) temperature dependent winter NSC metabolism, and (III) spring NSC remobilization and redistribution processes.

Overland movement and migration phenology in relation to breeding of Arctic Terns Sterna paradisaea

It is often implicitly assumed that seabirds migrate using marine environments, but this assumption is increasingly being challenged by electronic tracking data. The arrival and departure routes of Arctic Terns breeding on the North Sea coast of the United Kingdom (UK) are unknown but there has been speculation about the possibility of overland migration. Analysis of light‐level geolocator data from birds breeding on the Farne Islands suggests that these birds arrived and left their North Sea colony overland via the Irish Sea, rather than taking coastal routes along the east coast of the UK and through the English Channel. In addition, some departing birds may enter the North Atlantic by crossing Ireland rather than through the Irish Sea. The direction of arrival in spring had a more southerly orientation than the direction of autumn departure. The geolocator data allow migration phenology in relation to breeding to be defined and indicated that the birds arrived around 15 days before the first eggs were laid in the colony. Departure timing may be determined by seasonal progression and not markedly influenced by breeding success. This study supports the idea that overland migration may be a more widespread and consistent strategy for seabirds than has been realized.

Earlier spring passage of ‘Greenlandic’ Northern Wheatears Oenanthe o. leucorhoa on the coast of Belgium

ABSTRACT In temperate regions many migratory bird species have advanced their spring arrival to the breeding grounds in recent decades but such changes are much less known among Arctic species. Here we report on long-term changes in the spring passage of ‘Greenlandic’ Northern Wheatears (Oenanthe o. leucorhoa), as revealed by trapping and ringing along the coast of southwestern Belgium. Between 1990 and 2018, these wheatears advanced their average timing of spring passage by 2.9 days for females and by 2.5 days for males. Neither regional weather variables in spring nor the North Atlantic Oscillation Index was found to be correlated with these changes.

Large scale climate affects the timing of spring arrival but local weather determines the start of breeding in a northern Little Tern (Sternula albifrons) population

In migratory birds, the timing of arrival to the breeding grounds can be affected by weather on the migration routes and breeding sites at arrival. Timing of breeding can be affected by arrival dates but also by local weather conditions during the pre-breeding period. Because long-distance migrants arrive and breed late in the season, weather is thought to be less important, but more information is needed especially from seabirds that are vulnerable to climatic effects. I used observation data from the Little Tern (Sternula albifrons), a long-distance migrant, made by bird watchers during 2006–2016 to examine whether their spring arrival to the breeding grounds in Finland is associated with the large-scale weather pattern (the North Atlantic Oscillation; NAO index) or local weather. In addition, I used breeding data to examine whether the start of egg laying is associated with the annual first arrival dates, local weather or the NAO index. Spring arrival was associated with large scale weather patterns rather than local weather conditions.

Phenology of migrations of the Black Stork in Ukraine in 1976-2016

Timing of the first arrival in spring, start and end of the autumn migration were summarized and analyzed for the period in 41 years. In spring, Black Storks arrived in different regions as a rule since the second ten-day of March till the second half of April. Mean dates fell on late March and early April. The autumn migration began since late July and early August till September, on average it started during the second and third ten-day of August. Last departures were observed since the third ten-day of August till October or even November, mean dates in majority of regions fell on the second and third ten-days of September. The autumn migration lasted about a month. Variation of timing increased in series: first arrival – start of autumn migration – last departure. Timing of spring arrival advanced to earlier dates, timing of autumn migration remained stable.

Shifts in hatch dates do not provide pied flycatchers with a rapid ontogenetic route to adjust offspring time schedules to climate change

Abstract Environments change rapidly, and it is unclear whether organisms with complex life‐styles, such as avian migrants, are able to adjust sufficiently. For understanding human impacts on ecosystem functioning, it is crucial to understand how well, and by which mechanisms species are able to adapt. To improve the understanding of migrants’ ability to adjust their annual timing to climate change, we investigated ontogenetic hatch date effects on adult spring migration timing and female egg‐laying dates. We experimentally delayed hatch dates of pied flycatchers Ficedula hypoleuca by 1 week in three breeding seasons by delaying incubation onset. We investigated if natural and experimental (shifts in) hatch date affected timing of recruiting individuals up to at least 3 years after the manipulation. Spring arrival dates were positively correlated with natural variation in hatch dates in three of the 5 years considered, but no such effects were found in egg laying. Experiments showed that delayed hatching resulted in delayed arrival and laying only in 1‐year‐old and not in older birds. These effects were mostly observed during one of the study years. The discrepancy between experimental and natural hatch date effects indicates that a causal hatch date effect is not generally responsible for the correlation between a birds’ birth date and timing during adulthood. Instead, we propose that natural hatch date effects on spring arrival arise from genetic variation in migration schedules, while delays in hatching induced carry‐over effects on arrival and laying dates in offspring (e.g. the experimental effect in 2010). Strong support for year‐specific expression of hatch date and delay effects on time schedules imply that trait‐variation can be easily obscured. The latter may explain the lack of hatch date effects on female egg laying. Our results imply that plasticity in breeding phenology does not provide pied flycatchers with a non‐genetic inheritance route to rapidly advance annual cycles. Instead, plasticity may rather masks (genetic) trait‐variation for selection to act on, and thereby slow down micro‐evolutionary adaptation to changing environments. A plain language summary is available for this article.

Contrasting spring arrival dates of two shorebirds in N Norway

Contrasting spring arrival dates of two shorebirds in N Norway

Potential for an Arctic-breeding migratory bird to adjust spring migration phenology to Arctic amplification.

Arctic amplification, the accelerated climate warming in the polar regions, is causing a more rapid advancement of the onset of spring in the Arctic than in temperate regions. Consequently, the arrival of many migratory birds in the Arctic is thought to become increasingly mismatched with the onset of local spring, consequently reducing individual fitness and potentially even population levels. We used a dynamic state variable model to study whether Arctic long-distance migrants can advance their migratory schedules under climate warming scenarios which include Arctic amplification, and whether such an advancement is constrained by fuel accumulation or the ability to anticipate climatic changes. Our model predicts that barnacle geese Branta leucopsis suffer from considerably reduced reproductive success with increasing Arctic amplification through mistimed arrival, when they cannot anticipate a more rapid progress of Arctic spring from their wintering grounds. When geese are able to anticipate a more rapid progress of Arctic spring, they are predicted to advance their spring arrival under Arctic amplification up to 44days without any reproductive costs in terms of optimal condition or timing of breeding. Negative effects of mistimed arrival on reproduction are predicted to be somewhat mitigated by increasing summer length under warming in the Arctic, as late arriving geese can still breed successfully. We conclude that adaptation to Arctic amplification may rather be constrained by the (un)predictability of changes in the Arctic spring than by the time available for fuel accumulation. Social migrants like geese tend to have a high behavioural plasticity regarding stopover site choice and migration schedule, giving them the potential to adapt to future climate changes on their flyway.

Weather conditions and variation in timing of spring and fall migrations of migratory caribou

Species that make long-distance migrations face changes in the phenology of natural processes linked to global climate changes. Mismatch between the onset of resources and arrival on breeding grounds or changes in the conditions faced during migration such as early snowmelt in northern environments could have severe impacts on migrant populations. We investigated the impact of local weather and broad-scale climate and of the availability of forage resources on timing of spring and fall migrations of migratory caribou ( Rangifer tarandus ) from the Riviere-George and Riviere-aux-Feuilles herds in northern Quebec and Labrador, Canada. We tested the effect of local weather using data provided by the Canadian Regional Climate Model, a large-scale climate index, snow and ice cover, and the Normalized Difference Vegetation Index on departure and arrival dates of 377 spring migrations and 499 fall migrations of female caribou. Since 2000, except for the spring arrival, migrations tended to occur earlier. Spring arrival was delayed when caribou encountered mild temperatures and abundant precipitation during migration, as early snowmelt may increase cost of movements. At greater population sizes, caribou seemed to limit the time spent on summer range by arriving later and departing earlier, possibly to limit competition for summer forage. During fall, caribou adjusted their migration to conditions en route because they arrived earlier if November was snowy and mild, possibly to limit the costs of moving through deep snow. Like numerous migrant species, most caribou herds are declining, and it is crucial to assess which environmental factors affect migrant populations. Our study contributes to the understanding of the impact of local weather conditions and climate change on migratory land mammals.

The early birds and the rest: do first nesters represent the entire colony?

Climate change studies have detected earlier spring arrival of breeding birds. However, first nest dates (date first nests were found), which commonly provide the metric for earlier arrival, can be biased by population size or sampling effort. Our aims were to determine if: 1) first nest dates and median nest date (date when at least 50 % of all females have nested) were equivalent predictors for the spring arrival and 2) first nest date or median nest date were related to nest numbers. We recorded first and median nest dates and nest numbers at the common eider (Somateria mollissima) colony at Rif, Iceland, during 1992–2013. First nest date was advanced by 11 days during the study, but median nest date was advanced by only 4 days. First nest date and median nest date were correlated, but this relationship was only a small improvement over the null model (Nagelkerke R2 = 30 %). We found a relationship with nest count for both first and median nest dates once the analysis had accounted for inter-annual variability. First nest date may not represent the colony as a whole but rather the physically fittest or the most determined individuals, which may be more prone to nest early than the general population. Nesting birds must decide how much to advance breeding based on nest numbers and other non-temporal cues which necessitate earlier breeding. We argue that nest numbers affect the birds in a biological sense and that the advancement was not explained solely by increased nest numbers.

Upwind or downwind: the spring arrival of Arctic Terns Sterna paradisaea at Troms, north Norway

ABSTRACTArctic Terns Sterna paradisaea have a record long migration between their breeding grounds in the Arctic and wintering areas in the Antarctic. Nevertheless, return dates to north Norway were remarkably constant over a 35-year period (1981–2015), with Arctic Terns arriving in Troms within a 13-day time window in mid to late May. Since 1993, arrival dates have advanced by about four days. No relationships were found between arrival dates and large-scale weather proxies such as the North Atlantic Oscillation or sea temperatures, but when terns were approaching Troms, headwinds tended to delay arrivals whereas tailwinds advanced them.

Repeatability in Spring Arrival Dates in Pied Flycatchers Varies Among Years and Sexes

Timing of arrival in long-distance migration could have fitness consequences: arrival too early impairs survival chances, whereas arrival too late reduces current reproductive success. Evolution thus may have favoured a phenotype that arrived at the optimal time. However, individuals within populations of longdistance migrant species arrive over a considerable time span, and often show consistency in whether they are early or late. This repeatability in arrival varies between studies, and we hypothesise it to be affected by conditions encountered en route or in winter. Here we report on the spring arrival dates of Pied Flycatchers Ficedula hypoleuca to their Dutch breeding sites during eight consecutive years. Our field estimates of arrival were highly accurate, as validated by geolocator data on 13 individuals. Years differed in mean arrival dates. Within years and sexes, arrival date generally spanned more than two weeks. First-year individuals arrived on average 4–5 days later than older individuals. U...

Interactions between a Candidate Gene for Migration (ADCYAP1), Morphology and Sex Predict Spring Arrival in Blackcap Populations.

Avian research has begun to reveal associations between candidate genes and migratory behaviors of captive birds, yet few studies utilize genotypic, morphometric, and phenological data from wild individuals. Previous studies have identified an association between ADCYAP1 polymorphism and autumn migratory behavior (restlessness, or zugunruhe), but little is known about the relationship between ADCYAP1 and spring migratory behavior. The timing of spring migration and arrival to the breeding ground are phenological traits which could be particularly favorable for establishing territories and acquiring mates, thus important to fitness and reproductive success. Here, we investigated how individual genotypic ADCYAP1 variation and phenotypic variation (wing length and shape) of blackcaps (Sylvia atricapilla) affect spring arrival date across nine natural populations in Europe. We hypothesized that longer alleles should be associated with earlier spring arrival dates and expected the effect on arrival date to be stronger for males as they arrive earlier. However, we found that longer wings were associated with earlier spring arrival to the breeding grounds for females, but not for males. Another female-specific effect indicated an interaction between ADCYAP1 allele size and wing pointedness on the response of spring arrival: greater allele size had a positive effect on spring arrival date for females with rounder wings, while a negative effect was apparent for females with more pointed wings. Also, female heterozygotes with pointed wing tips arrived significantly earlier than both homozygotes with pointed wings and heterozygotes with round wings. Stable isotope ratios (δ 2 H) of a subset of blackcaps captured in Freiburg in 2011 allowed us also to assign individuals to their main overwintering areas in northwest (NW) and southwest (SW) Europe. NW males arrived significantly earlier to the Freiburg breeding site than both SW males and females in 2011. NW females had more pointed wing tips compared to SW females, but no difference in ADCYAP1 allele size was found between the different migration routes.

THE INFLUENCE OF CLIMATIC ANOMALIES ON THE ANIMALS IN MIDDLE LATITUDES OF THE EAST OF THE RUSSIAN PLAIN

With a steady climate change increases the risk of weather anomalies. The droughts, forest fires, winter frosts become more frequent that affects the abundance and diversity of animals, including commercial species and crop pests. The deviation of timing of the phases of ontogeny from multiyear is a sensitive indicator of the state and the processes of ecosystems. In order to identify the features of the biota response to extreme weather conditions we studied the reaction of animals of the East Russian Plain (Kirov Region) to weather anomalies of cold winter in 2009-2010 and the hot summer of 2010 according to phenological (1890-2013 years) and phytosanitary (2000-2013 years) monitoring of 52 species Clitellata, Bivalvia, Gastropoda, Insecta, Aves, Mammalia. The observations were carried out on the territory of the boreal ecotone with different changes of hydrothermal regime within Vyatsko-Verkhnekamsk District of the Volga Region. The phenological monitoring carried out by a standard technique involving public opinion poll from permanent correspondents. We analyzed the date of the seasonal phases of development: the end of winter diapause, the beginning of oviposition, hatching of eggs, the emergence of the imago insects; spring arrival, the beginning of the breeding cycle, autumn departure of birds and others. In 2010 the survey of additional information on phenology of biological objects was conducted by method of questioning of permanent observers in 23 geographical locations of the Kirov Region. We examined the impact of agroclimatic conditions for the development of pests within permanent control areas of Kumenskii Hospital District Department of the Federal Phytosanitary Service during the active vegetation. Long frosts below 35 С were pessimal and sublethal for different stages of ontogenesis in Leptinotarsa decemlineata, Aelia acuminata, Agrotis segetum, Oscinnella frit and others. Extreme summer heat above 30 °C and drought were pessimal for Phyllotreta vittula, Leptinotarsa decemlineata and sublethal for eggs and larvae of Oscinnella frit, Aelia acuminata, Elateridae, but contributed to the early emergence of Apion apricans adults. Exceeding monthly average air temperature at the 1 С resulted in advancing the timing of microthermal insects development by 1.9 days and advancing the arrival dates of near migrant birds by 1 day in April, and in advancing the timing of mesothermal insects development by 1.3 days and advancing the arrival dates of distant migrant birds by 1.4 day in May. The 100 С excess of the effective temperature in May led to emergence of Oscinnella frit, Leptinotarsa decemlineata, Pieris brassicae adults 2.9-3.8 days ahead of due time. In June it resulted in larvae emerging 2.7-4.8 days ahead of due time, and in July their adult summer generation occurred 1.6-1.7 days earlier. Negative impact of pests on crops in abnormal seasons can be reduced by spring crops sowing in early summer, while winter rye should optimally be sowed in later date. In the conditions of mid-latitude of Eastern European Plain the temperatures below 40 С in winter and long heat up to 40 С with a summer drought are within the adaptive capacities of the regional biota. Their influence does not cause irreversible consequences in the functioning of wildlife, particularly animals, including pests.

Changes in the timing of departure and arrival of Irish migrant waterbirds.

There have been many recent reports across Europe and North America of a change in the timing of arrival and departure of a range of migrant bird species to their breeding grounds. These studies have focused primarily on passerine birds and climate warming has been found to be one of the main drivers of earlier arrival and departure in spring. In Ireland, rising spring temperature has been shown to result in the earlier arrival of sub-Saharan passerine species and the early departure of the Whooper Swan. In order to investigate changes in spring arrival and departure dates of waterbirds to Ireland, we extracted latest dates as an indicator of the timing of departure of winter visitors (24 species) and earliest dates as an indicator of the timing of arrival of spring/summer migrants (2 species) from BirdWatch Ireland’s East Coast Bird reports (1980–2003). Three of the winter visitors showed evidence of later departure and one of earlier departure whereas one of the spring/summer visitors showed evidence of earlier arrival. In order to determine any influence of local temperature on these trends, we analysed data from two synoptic weather stations within the study area and found that spring (average February, March and April) air temperature significantly (P < 0.05) increased at a rate of 0.03 °C per year, which was strongly correlated with changes in latest and earliest records. We also tested the sensitivity of bird departure/arrival to temperature and found that Northern Pintail would leave 10 days earlier in response to a 1 °C increase in spring temperature. In addition, we investigated the impact of a large-scale circulation pattern, the North Atlantic Oscillation (NAO), on the timing of arrival and departure which correlated with both advances and delays in departure and arrival. We conclude that the impact of climate change on earliest and latest records of these birds is, as expected, species specific and that local temperature had less of an influence than large-scale circulation patterns.

Change in spring arrival of migratory birds under an era of climate change, Swedish data from the last 140 years.

Many migratory bird species have advanced their spring arrival during the latest decades, most probably due to climate change. However, studies on migratory phenology in the period before recent global warming are scarce. We have analyzed a historical dataset (1873–1917) of spring arrival to southern and central Sweden of 14 migratory bird species. In addition, we have used relative differences between historical and present-day observations (1984–2013) to evaluate the effect of latitude and migratory strategy on day of arrival over time. There was a larger change in spring phenology in short-distance migrants than in long-distance migrants. Interestingly, the results further suggest that climate change has affected the phenology of short-distance migrants more in southern than in central Sweden. The results suggest that the much earlier calculated arrival to southern Sweden among short-distance migrants mirrors a change in location of wintering areas, hence, connecting migration phenology and wintering range shifts.

Variation in age composition among colony sizes in Cliff Swallows.

Variation in group size is characteristic of most social species. The extent to which individuals sort among group sizes based on age may yield insight into why groups vary in size and the age-specific costs and benefits of different social environments. We investigated the age composition of Cliff Swallow (Petrochelidon pyrrhonota) colonies of different sizes over 18 years at a long-term study site in western Nebraska, USA. Using years elapsed since banding as a relative measure of age for over 194,000 birds, we found that the proportion of age-class-1 swallows (birds banded as nestlings or juveniles or adults in the year of banding) of both sexes increased in larger colonies and at colony sites becoming active later in the summer. Age composition was unrelated to how often a particular colony site was used. The effect of colony size most likely reflected the fact that older birds return to the same colony site in successive years even when the colony size there decreases, and that yearlings and immigrants benefit more from larger colonies than do older, more experienced individuals. The date effect probably resulted in part from later spring arrival by younger and/or immigrant swallows. At fumigated sites where ectoparasitic swallow bugs (Oeciacus vicarius) had been removed, age composition did not vary with either colony size or colony initiation date. The patterns reported here appear to be driven partially by the presence of ectoparasites and suggest that the hematophagous bugs influence variation in Cliff Swallow group composition. Our results are consistent with the hypothesis that variation in colony size reflects, in part, age-based sorting of individuals among groups.

Estimating unbiased phenological trends by adapting site-occupancy models.

As a response to climate warming, many animals and plants have been found to shift phenologies, such as appearance in spring or timing of reproduction. However, traditional measures for shifts in phenology that are based on observational data likely are biased due to a large influence of population size, observational effort, starting date of a survey, or other causes that may affect the probability of detecting a species. Understanding phenological responses of species to climate change, however, requires a robust measure that could be compared among studies and study years. Here, we developed a new method for estimating arrival and departure dates based on site-occupancy models. Using simulated data, we show that our method provided virtually unbiased estimates of phenological events even if detection probability or the number of sites occupied by the species is changing over time. To illustrate the flexibility of our method, we analyzed spring arrival of two long-distance migrant songbirds and the length of the flight period of two butterfly species, using data from a long-term biodiversity monitoring program in Switzerland. In contrast to many birds that migrate short distances, the two long-distance migrant songbirds tended to postpone average spring arrival by -0.5 days per year between 1995 and 2012. Furthermore, the flight period of the short-distance-flying butterfly species apparently became even shorter over the study period, while the flight period of the longer-distance-flying butterfly species remained relatively stable. Our method could be applied to temporally and spatially extensive data from a wide range of monitoring programs and citizen science projects, to help unravel how species and communities respond to global warming.