Extreme spring conditions in the Arctic delay spring phenology of long-distance migratory songbirds

Arctic regions are warming rapidly, with extreme weather events increasing in frequency, duration, and intensity just as in other regions. Many studies have focused on how shifting seasonality in environmental conditions affects vegetation phenology, while far fewer have examined how the breeding phenology of arctic fauna responds. We studied two species of long-distance migratory songbirds, Lapland longspurs, Calcarius lapponicus, and white-crowned sparrows, Zonotrichia leucophrys gambelii, across five consecutive breeding seasons in northern Alaskan tundra. We aimed to understand how spring environmental conditions affected breeding cycle phenology, including the timing of arrival on breeding grounds, territory establishment, and clutch initiation. Spring temperatures, precipitation, and snow-free dates differed significantly among years, with 2013 characterized by unusually late snow cover. In response, we found a significant delay in breeding-cycle phenology for both study species in 2013 relative to other study years: the first bird observed was delayed by 6–10 days, with mean arrival by 3–6 days, territory establishment by 6–13 days, and clutch initiation by 4–10 days. Further, snow cover, temperature, and precipitation during the territory establishment period were important predictors of clutch initiation dates for both species. These findings suggest that Arctic-breeding passerine communities may have the flexibility required to adjust breeding phenology in response to the increasingly extreme and unpredictable environmental conditions—although future generations may encounter conditions that exceed their current range of phenological flexibility.     

Winter rainfall predicts phenology in widely separated populations of a migrant songbird

Climate change is affecting behaviour and phenology in many animals. In migratory birds, weather patterns both at breeding and at non-breeding sites can influence the timing of spring migration and breeding. However, variation in responses to weather across a species range has rarely been studied, particularly among populations that may winter in different locations. We used prior knowledge of migratory connectivity to test the influence of weather from predicted non-breeding sites on bird phenology in two breeding populations of a long-distance migratory bird species separated by 3,000 km. We found that winter rainfall showed similar associations with arrival and egg-laying dates in separate breeding populations on an east–west axis: greater rainfall in Jamaica and eastern Mexico was generally associated with advanced American redstart (Setophaga ruticilla) phenology in Ontario and Alberta, respectively. In Ontario, these patterns of response could largely be explained by changes in the behaviour of individual birds, i.e., phenotypic plasticity. By explicitly incorporating migratory connectivity into responses to climate, our data suggest that widely separated breeding populations can show independent and geographically specific associations with changing weather conditions. The tendency of individuals to delay migration and breeding following dry winters could result in population declines due to predicted drying trends in tropical areas and the tight linkage between early arrival/breeding and reproductive success in long-distance migrants.     

Something for the weekend? Examining the bias in avian phenological recording

In this paper we examine the bias towards weekend recording (the weekend effect) in volunteer phenology, using over 14,000 bird migration phenological observations from eight locations in the UK as a data source. Data from 45 bird species were used. Overall, 44% of all records were taken at weekends in contrast to the 28.6% (i.e. two out of seven days) that would be expected if records were evenly spread throughout the week. Whilst there is documented evidence of environmental differences at weekends, particularly in large urban areas, we believe the weekend effect is mostly a consequence of greater recorder effort at weekends. Some birds, likely to be obvious by their behaviour or abundance, had fewer weekend records than the remaining species. The weekend effect, to some extent, differed between locations and between seasons. There was some evidence that, particularly in autumn, the weekend bias may be lessening. If so, this will increase the accuracy of phenological records, making the detection of changes and responses to temperature easier.     

Winter habitat use does not influence spring arrival dates or the reproductive success of Yellow Warblers breeding in the arctic

Winter habitat use can influence the breeding success of migratory songbirds in temperate regions due to its impact on bird condition and breeding phenology. How such carry-over effects vary with latitude is unknown. To address this question, we examined how winter habitat use, inferred from δ¹³C and δ¹⁵N signatures in winter-grown feathers, influenced the breeding phenology and productivity of Yellow Warblers (Setophaga petechia) at the extreme north of their range in the Canadian arctic (68°N) and compared this population with midlatitude Yellow Warbler (51°N) and American Redstart (Setophaga ruticilla; 44°N) populations reported in previous studies. In the arctic, we examined male arrival dates, female clutch initiation dates and the relationship between these timing variables and the number and quality of offspring produced within the season. In contrast to warblers breeding at midlatitudes, we find no support for an impact of winter habitat use on breeding phenology or productivity. Male arrival dates and female clutch initiation dates in both young and older individuals were not correlated with isotopic signatures acquired on the wintering grounds. Males with enriched δ¹⁵N signatures paired more rapidly after arrival, indicating a possible relationship between winter habitat use and condition. This relationship did not enhance annual productivity for these individuals, however, as the negative relationship between breeding phenology and reproductive success in our arctic population was significantly weaker than among Yellow Warblers breeding further south. This reduction or absence of timing effects on productivity in the north effectively removes one pathway through which carry-over effects can act.     

Spatiotemporal variation in avian migration phenology: citizen science reveals effects of climate change

A growing number of studies have documented shifts in avian migratory phenology in response to climate change, and yet there is a large amount of unexplained variation in the magnitude of those responses across species and geographic regions. We use a database of citizen science bird observations to explore spatiotemporal variation in mean arrival dates across an unprecedented geographic extent for 18 common species in North America over the past decade, relating arrival dates to mean minimum spring temperature. Across all species and geographic locations, species shifted arrival dates 0.8 days earlier for every °C of warming of spring temperature, but it was common for some species in some locations to shift as much as 3-6 days earlier per °C. Species that advanced arrival dates the earliest in response to warming were those that migrate more slowly, short distance migrants, and species with broader climatic niches. These three variables explained 63% of the interspecific variation in phenological response. We also identify a latitudinal gradient in the average strength of phenological response, with species shifting arrival earlier at southern latitudes than northern latitudes for the same degree of warming. This observation is consistent with the idea that species must be more phenologically sensitive in less seasonal environments to maintain the same degree of precision in phenological timing.     

Spatial patterns of white stork (Ciconia ciconia) migratory phenology in the Iberian Peninsula

In contrast to the attention attracted by temporal trends of phenology, the spatial patterns of arrivals, departures or stays of trans-Saharan birds are still nowadays largely unknown in most of their European breeding areas. In the case of the white stork (Ciconia ciconia), some studies have attempted to describe its migratory patterns throughout some European countries but, to our knowledge, no one has related these patterns to some kind of explanatory variable which offers an ecologically-based explanation for the heterogeneous phenology observable among populations. Here, arrivals, departures and stays of this species, recorded in hundreds of Spanish localities, were related to a set of environmental, geographical, biological and spatial predictors, and modeled by multiple regression. The best model for arrival dates accounted for up to 34% of variability of data and pointed towards an earlier arrival in those populations located in south-western Iberia and with higher population densities. This last relationship is probably due to the competition for nest-site fidelity maintenance. However, no variable was able to explain properly the blurred spatial pattern recorded for departure dates. Departure decisions are strongly influenced by social behavior in this species and depend on collective decisions influenced by peculiar local environmental conditions of each year rather than macrogeographical gradients. Environmental, geographical or spatial variables also did not capture much of the observed variability in the length of the stays among populations. However, this variable was strongly related to the arrival and departure dates of populations. White storks stay longer in localities with earlier arrivals and, especially, later departures.     

Climate change and bird phenology: a long-term study in the Iberian Peninsula

Many studies in recent years have demonstrated long‐term temporal trends in biological parameters that can only be explained by climate change. Bird phenology has received great attention, as it studies one of the most conspicuous, popular, and easily observable phenomena in nature. There are many studies of long‐term changes in spring arrival dates, most of which concur with earlier records from the last few decades. However, few data are available for autumn departures or length of stays. Furthermore, existing data offer an equivocal picture. In this study, we analysed a huge database of about 44 000 records for five trans‐Saharan bird species (Ciconia ciconia, Cuculus canorus, Apus apus, Hirundo rustica and Luscinia megarhynchos). Data were collected from over 1300 sites around Spain during the period 1944–2004. Common spring arrival patterns were found in all species. Spring arrival dates have tended to advance since the mid‐1970s. Current dates are similar to those from the 1940s (except for C. ciconia). Thus, the advance of spring migration over the last three decades could be seen as a return to the initial timing of arrival dates, after abnormally delayed arrivals during the 1970s. A strong negative relationship with temperature in Spain at arrival time was observed in all species. A negative relationship with the Sahel Index (a measurement of precipitation in the African Sahel area during the rainy season) for the previous year was also found in C. canorus, A. apus and H. rustica. Regarding autumn departures, all species showed common interdecadal fluctuations, but only H. rustica is leaving earlier Spain at present. All species departed earlier in years that had higher temperatures during their reproductive period. However, only for H. rustica the relation between Spanish temperatures at departure time and the last sightings of individuals was significant. A heterogeneous temporal response for the length of stay was also found: C. ciconia increased, A. apus did not change and H. rustica decreased its stay. This is the first study, based on an extensive bird phenology observational network covering a large region, that shows the most complete and thorough analysis available for the Mediterranean region.     

Is there a weekend bias in clutch-initiation dates from citizen science? Implications for studies of avian breeding phenology

Accurate phenology data, such as the timing of migration and reproduction, is important for understanding how climate change influences birds. Given contradictory findings among localized studies regarding mismatches in timing of reproduction and peak food supply, broader-scale information is needed to understand how whole species respond to environmental change. Citizen science—participation of the public in genuine research—increases the geographic scale of research. Recent studies, however, showed weekend bias in reported first-arrival dates for migratory songbirds in databases created by citizen-science projects. I investigated whether weekend bias existed for clutch-initiation dates for common species in US citizen-science projects. Participants visited nests on Saturdays more frequently than other days. When participants visited nests during the laying stage, biased timing of visits did not translate into bias in estimated clutch-initiation dates, based on back-dating with the assumption of one egg laid per day. Participants, however, only visited nests during the laying stage for 25 % of attempts of cup-nesting species and 58 % of attempts in nest boxes. In some years, in lieu of visit data, participants provided their own estimates of clutch-initiation dates and were asked “did you visit the nest during the laying period?” Those participants who answered the question provided estimates of clutch-initiation dates with no day-of-week bias, irrespective of their answer. Those who did not answer the question were more likely to estimate clutch initiation on a Saturday. Data from citizen-science projects are useful in phenological studies when temporal biases can be checked and corrected through protocols and/or analytical methods.     

Adult male birds advance spring migratory phenology faster than females and juveniles across North America

Advances in spring migratory phenology comprise some of the most well-documented evidence for the impacts of climate change on birds. Nevertheless, surprisingly little research has investigated whether birds are shifting their migratory phenology equally across sex and age classes—a question critical to understanding the potential for trophic mismatch. We used 60 years of bird banding data across North America—comprising over 4 million captures in total—to investigate both spring and fall migratory phenology for a total of 98 bird species across sex and age classes, with the exact numbers of species for each analysis depending on season-specific data availability. Consistent with protandry, in spring (n = 89 species), adult males were the first to arrive and immature females were the last to arrive. In fall (n = 98), there was little difference between sexes, but adults tended to depart earlier than juveniles. Over 60 years, adult males advanced their phenology the fastest (−0.84 days per decade, 95 CrI = −1.22 to −0.47, n = 36), while adult and immature females advanced at a slower pace, causing the gap in male and female arrival times to widen over time. In the fall, there was no overall trend in phenology by age or sex (n = 57), driven in part by high interspecific variation related to breeding and molt strategies. Our results indicate consistent and predictable age- and sex-based differences in the rates at which species' springtime phenology is shifting. The growing gap between male and female migratory arrival indicates sex-based plasticity in adaptation to climate change that has strong potential to negatively impact current and future population trends.     

Long‐term changes in the migration phenology of UK breeding birds detected by large‐scale citizen science recording schemes

The timing of migration is one of the key life‐history parameters of migratory birds. It is expected to be under strong selection, to be sensitive to changing environmental conditions and to have implications for population dynamics. However, most phenological studies do not describe arrival and departure phenologies for a species in a way that is robust to potential biases, or that can be clearly related to breeding populations. This hampers our ability to understand more fully how climate change may affect species’ migratory strategies, their life histories and ultimately their population dynamics. Using generalized additive models (GAMs) and extensive large‐scale data collected in the UK over a 40‐year period, we present standardized measures of migration phenology for common migratory birds, and examine how the phenology of bird migration has changed in the UK since the 1960s. Arrival dates for 11 of 14 common migrants became significantly earlier, with six species advancing their arrival by more than 10 days. These comprised two species, Blackcap Sylvia atricapilla and Chiffchaff Phylloscopus collybita, which winter closest to Britain in southern Europe and the arid northern zone of Africa, Common Redstart Phoenicurus phoenicurus, which winters in the arid zone, and three hirundines (Sand Martin Riparia riparia, House Martin Delichon urbicum and Barn Swallow Hirundo rustica), which winter in different parts of Africa. Concurrently, departure dates became significantly later for four of the 14 species and included species that winter in southern Europe (Blackcap and Chiffchaff) and in humid zones of Africa (Garden Warbler Sylvia borin and Whinchat Saxicola rubetra). Common Swift Apus apus was the exception in departing significantly earlier. The net result of earlier arrival and later departure for most species was that length of stay has become significantly longer for nine of the 14 species. Species that have advanced their timing of arrival showed the most positive trends in abundance, in accordance with previous studies. Related in part to earlier arrival and the relationship above, we also show that species extending their stay in Great Britain have shown the most positive trends. Further applications of our modelling approach will provide opportunities for more robust tests of relationships between phenological change and population dynamics than have been possible previously.     

Phenology and climate change: a long-term study in a Mediterranean locality

It is well documented that plant and animal phenology is changing in response to recent climate warming in the Palaearctic. However, few long-term data sets are currently available in the Mediterranean basin. The present study reports long-term temporal trends of several phenophases of 45 plants, 4 insects and 6 migratory insectivorous birds. Dynamic factor analyses performed with plant phenophases showed that most of those events occurring at spring and summer had common trends toward the advancement, especially since mid-1970s. However, during these last decades, insect phenology showed a steeper advance than plant phenology, suggesting an increase of decoupling of some plant–insect interactions, such as those between pollinators and flowers or herbivorous insects and their plant resources. All trans-Saharan bird species showed highly significant temporal trends in all studied phenophases (some of them covering most of the last century). In two species, the duration of stay is increasing due to both earlier arrivals and later departures. On the other hand, two wintering species showed a significant advancement in their arrival dates, while an opposite pattern were found for departures of each one. Only one of these species increased significantly its wintering stay. Bird departures were not related to local climate in any species. Our results demonstrate a key role of local temperatures behind interannual variability of most plant and insects phenophases, with especial emphasis in those occurring in spring and summer. Therefore, the common signal towards the advancement recorded since mid-1970s resulted from the recent rise in temperatures.     

Examining carry‐over effects of winter habitat on breeding phenology and reproductive success in prairie warblers Setophaga discolor

Winter habitat quality can influence breeding phenology and reproductive success of migratory birds. Using stable isotope ratios of carbon (δ¹³C) from bird claws and red blood cells collected in Massachusetts, USA, we assessed if winter habitat occupancy carried over to affect prairie warbler Setophaga discolor breeding arrival dates, body condition upon arrival, pairing success, first‐egg dates and reproductive success. In two of three years (in 2011 and 2012, but not in 2013), after‐second‐year (ASY) males wintering in drier habitat, as indicated by enriched δ¹³C values, arrived later on the breeding grounds. Based on the North Atlantic Oscillation index, there was likely less rainfall in the Caribbean wintering grounds during the winters of 2011 and 2012 compared to the winter of 2013, suggesting increased winter rainfall in 2013 may have diminished the influence of winter habitat occupancy on arrival date. We did not find any effects of winter habitat on breeding season phenomena for second‐year (SY) males or females, but our sample sizes for these age/sex classes were relatively low. Although winter habitat quality influenced arrival dates of ASY males, there was no evidence that it affected reproductive performance, perhaps because of high rates of nest depredation in our system. Our study adds to a growing body of research that shows the influence of carry‐over effects can differ among species and within populations, and also can be modulated by other environmental conditions. This information enriches our understanding of the role of carry‐over effects in population limitation for migratory birds.     

Can we detect change in the phenology of winter migrant birds in the UK?

Although there is very strong evidence for an advance in the spring arrival dates of migrating birds, there are few data with which to examine the changes, if any, in the dates of winter migration. In this paper we examine data on the first arrivals and last departures of winter visitors from two UK county bird reports. A small number of changes in phenology and some relationships with climatic variables were present. However, results were often contradictory or inconclusive. As data such as these are highly variable we recommend a more thorough examination for climatic impact where records exist.     

Climate and the complexity of migratory phenology: sexes,migratory distance,and arrival distributions

The intra- and inter-season complexity of bird migration has received limited attention in climatic change research. Our phenological analysis of 22 species collected in Chicago, USA, (1979–2002) evaluates the relationship between multi-scalar climate variables and differences (1) in arrival timing between sexes, (2) in arrival distributions among species, and (3) between spring and fall migration. The early migratory period for earliest arriving species (i.e., short-distance migrants) and earliest arriving individuals of a species (i.e., males) most frequently correlate with climate variables. Compared to long-distance migrant species, four times as many short-distance migrants correlate with spring temperature, while 8 of 11 (73%) of long-distance migrant species’ arrival is correlated with the North Atlantic Oscillation (NAO). While migratory phenology has been correlated with NAO in Europe, we believe that this is the first documentation of a significant association in North America. Geographically proximate conditions apparently influence migratory timing for short-distance migrants while continental-scale climate (e.g., NAO) seemingly influences the phenology of Neotropical migrants. The preponderance of climate correlations is with the early migratory period, not the median of arrival, suggesting that early spring conditions constrain the onset or rate of migration for some species. The seasonal arrival distribution provides considerable information about migratory passage beyond what is apparent from statistical analyses of phenology. A relationship between climate and fall phenology is not detected at this location. Analysis of the within-season complexity of migration, including multiple metrics of arrival, is essential to detect species’ responses to changing climate as well as evaluate the underlying biological mechanisms.     

The influence of climate on the timing and rate of spring bird migration

Ecological processes are changing in response to climatic warming. Birds, in particular, have been documented to arrive and breed earlier in spring and this has been attributed to elevated spring temperatures. It is not clear, however, how long-distance migratory birds that overwinter thousands of kilometers to the south in the tropics cue into changes in temperature or plant phenology on northern breeding areas. We explored the relationships between the timing and rate of spring migration of long-distance migratory birds, and variables such as temperature, the North Atlantic Oscillation (NAO) and plant phenology, using mist net capture data from three ringing stations in North America over a 40-year period. Mean April/May temperatures in eastern North America varied over a 5°C range, but with no significant trend during this period. Similarly, we found few significant trends toward earlier median capture dates of birds. Median capture dates were not related to the NAO, but were inversely correlated to spring temperatures for almost all species. For every 1°C increase in spring temperature, median capture dates of migratory birds averaged, across species, one day earlier. Lilac (Syringa vulgaris) budburst, however, averaged 3 days earlier for every 1°C increase in spring temperature, suggesting that the impact of temperature on plant phenology is three times greater than on bird phenology. To address whether migratory birds adjust their rate of northward migration to changes in temperature, we compared median capture dates for 15 species between a ringing station on the Gulf Coast of Louisiana in the southern USA with two stations approximately 2,500 km to the north. The interval between median capture dates in Louisiana and at the other two ringing stations was inversely correlated with temperature, with an average interval of 22 days, that decreased by 0.8 days per 1°C increase in temperature. Our results suggest that, although the onset of migration may be determined endogenously, the timing of migration is flexible and can be adjusted in response to variation in weather and/or phenology along migration routes.     

Early arriving males wait longer for a mate than later arrivals: the case of a migratory monogamous passerine bird species

Individuals that arrive earlier on the breeding grounds may obtain many advantages but they also have to spend time waiting for a mate. I studied the waiting times of male red-breasted flycatchers Ficedula parva, a small, migratory, sexually dichromatic passerine bird species under natural conditions (Bia?owie?a National Park, Poland) in relation to year, arrival time, age of male and morphological parameters. The length of waiting time was dependent on males’ arrival time. The males which arrived later waited a shorter time for females than earlier arrivals. In some years older males spent more time waiting for mates than younger males, but in other years they waited for shorter times. A significant interaction between age of male and year was also observed. Despite the significantly earlier arrival of older males, the waiting time was not related to male age. The waiting time was also not related to body biometric parameters of the male. Despite waiting longer, early male red-breasted flycatchers have an advantage over later arrivals given this greater chance of mating.     

How consistent are trends in arrival (and departure) dates of migrant birds in the UK?

We examine the first arrival and last departure dates of migrant bird species from, respectively, six and three English area bird reports. Of all 145 bird series, 50% demonstrated significantly earlier arrival in recent years, with the average advance over all species being 0.25 days/year or 12 days earlier over 50 years. Thirty percent of 67 series demonstrated significantly later departure, with the average species delay being 0.16 days/year or eight days later over 50 years. There was greater consistency between species in trends in first arrival than in last departure, with species such as sand martin Riparia riparia significantly earlier at all six sites while, for example, spotted flycatcher Muscicapa striata showed no significant change in arrival at all sites. Significant negative correlations between arrival dates and English temperatures were found for 26% of all series, but temperature effects on departures were less clear. We provide some evidence that trends in arrival dates may be masked by population declines in birds. Since migrant bird populations are in decline generally, this may suggest that the real advance in arrival dates may be greater than that reported here.     

Ticks collected from migratory birds,including a new record of Haemaphysalis formosensis,on Jeju Island,Korea

Migratory birds may disperse parasites across ecological barriers, and recent climate change may alter the pattern of ectoparasite dispersal via changed patterns of bird migration. In order to document the parasitization of migratory birds by Ixodidae ticks on Jeju Island in Korea, we examined 934 migratory birds comprising 75 species for ticks from 2010 to 2012. In total, 313 ticks were collected from 74 migratory birds across 17 avian species and identified based on morphological keys. These ticks represented six species: Haemaphysalis flava, H. formosensis, H. longicornis, H. concinna, Ixodes turdus and I. nipponensis. Of particular note was the presence of H. formosensis, a species not previously reported to have been found in Korea, and H. concinna, which had not been previously reported on Jeju Island. The dominant tick species found were H. flava (226 ticks, 72.2 %) and I. turdus (54 ticks, 17.3 %), and ground-dwelling thrushes such as Pale thrushes (Turdus pallidus; 39 birds, 52.7 %) were the most important hosts. Although H. longicornis is the most abundant and prevalent terrestrial tick on Jeju Island, the species accounted for only 3.8 % of the total ticks collected in this study, suggesting that ticks on migratory birds may differ from the local tick fauna and that exotic ticks may be introduced via migratory birds. Therefore, long-term programs for tick and tick-borne disease surveillance are recommended to understand the role of migratory animals in the introduction of exotic species and associated pathogens and in life cycles of ticks at different stages in this region.     

Polymorphism at the Clock gene predicts phenology of long‐distance migration in birds

Dissecting phenotypic variance in life history traits into its genetic and environmental components is at the focus of evolutionary studies and of pivotal importance to identify the mechanisms and predict the consequences of human‐driven environmental change. The timing of recurrent life history events (phenology) is under strong selection, but the study of the genes that control potential environmental canalization in phenological traits is at its infancy. Candidate genes for circadian behaviour entrained by photoperiod have been screened as potential controllers of phenological variation of breeding and moult in birds, with inconsistent results. Despite photoperiodic control of migration is well established, no study has reported on migration phenology in relation to polymorphism at candidate genes in birds. We analysed variation in spring migration dates within four trans‐Saharan migratory species (Luscinia megarhynchos; Ficedula hypoleuca; Anthus trivialis; Saxicola rubetra) at a Mediterranean island in relation to Clock and Adcyap1 polymorphism. Individuals with larger number of glutamine residues in the poly‐Q region of Clock gene migrated significantly later in one or, respectively, two species depending on sex and whether the within‐individual mean length or the length of the longer Clock allele was considered. The results hinted at dominance of the longer Clock allele. No significant evidence for migration date to covary with Adcyap1 polymorphism emerged. This is the first evidence that migration phenology is associated with Clock in birds. This finding is important for evolutionary studies of migration and sheds light on the mechanisms that drive bird phenological changes and population trends in response to climate change.     

Phenological advancement in arctic bird species: relative importance of snow melt and ecological factors

Previous studies have documented advancement in clutch initiation dates (CIDs) in response to climate change, most notably for temperate-breeding passerines. Despite accelerated climate change in the Arctic, few studies have examined nest phenology shifts in arctic breeding species. We investigated whether CIDs have advanced for the most abundant breeding shorebird and passerine species at a long-term monitoring site in arctic Alaska. We pooled data from three additional nearby sites to determine the explanatory power of snow melt and ecological variables (predator abundance, green-up) on changes in breeding phenology. As predicted, all species (semipalmated sandpiper, Calidris pusilla, pectoral sandpiper, Calidris melanotos, red-necked phalarope, Phalaropus lobatus, red phalarope, Phalaropus fulicarius, Lapland longspur, Calcarius lapponicus) exhibited advanced CIDs ranging from 0.40 to 0.80 days/year over 9 years. Timing of snow melt was the most important variable in explaining clutch initiation advancement (“climate/snow hypothesis”) for four of the five species, while green-up was a much less important explanatory factor. We found no evidence that high predator abundances led to earlier laying dates (“predator/re-nest hypothesis”). Our results support previous arctic studies in that climate change in the cryosphere will have a strong impact on nesting phenology although factors explaining changes in nest phenology are not necessarily uniform across the entire Arctic. Our results suggest some arctic-breeding shorebird and passerine species are altering their breeding phenology to initiate nesting earlier enabling them to, at least temporarily, avoid the negative consequences of a trophic mismatch.