Life-history attributes of Arctic-breeding birds drive uneven responses to environmental variability across different phases of the reproductive cycle

1. Animals exhibit varied life-history traits that reflect adaptive responses to their environments. For Arctic-breeding birds, traits like foraging guild, egg nutrient allocation, clutch size, and chick growth are predicted to be under increasing selection pressure due to rapid climate change and increasing environmental variability across high-latitude regions. 2. We compared four migratory birds (black brant [Branta bernicla nigricans], lesser snow geese [Chen caerulescens caerulescens], semipalmated sandpipers [Calidris pusilla], and Lapland longspurs [Calcarius lapponicus]) with varied life histories at an Arctic site in Alaska, USA, to understand how life-history traits help moderate environmental variability across different phases of the reproductive cycle. 3. We monitored aspects of reproductive performance related to the timing of breeding, reproductive investment, and chick growth from 2011–2018. 4. In response to early snow melt and warm temperatures, semipalmated sandpipers advanced their site arrival and bred in higher numbers, while brant and snow geese increased clutch sizes; all four species advanced their nest initiation dates. During chick rearing, longspur chicks were relatively resilient to environmental variation whereas warmer temperatures increased the growth rates of sandpiper chicks but reduced growth rates of snow goose goslings. These responses generally aligned with traits along the capital-income spectrum of nutrient acquisition and altricial-precocial modes of chick growth. Under a warming climate, the ability to mobilize endogenous reserves likely provides geese with relative flexibility to adjust the timing of breeding and the size of clutches. Warmer temperatures, however, may negatively affect the quality of herbaceous foods and slow gosling growth. 5. Species may possess traits that are beneficial during one phase of the reproductive cycle and others that may be detrimental at another phase, uneven responses that may be amplified with future climate warming. These results underscore the need to consider multiple phases of the reproductive cycle when assessing the effects of environmental variability on Arctic-breeding birds.

Liberalized harvest regulations have not affected overabundant Snow Geese in Northern Manitoba

Large amounts of money are spent each year to control overabundant species that imperil biodiversity and ecosystem functioning across the globe. Lesser Snow Geese (Anser caerulescens caerulescens) are emblematic of this issue, as their overabundance has affected a whole suite of plant, insect, and bird communities via a trophic cascade that managers have attempted to stop before it spreads further across the North American (sub)Arctic. To achieve this goal, liberalized harvest measures designed to decrease Lesser Snow Goose survival and abundance were implemented almost 2 decades ago. Our previous quantitative assessment of management effectiveness indicated that the growing Lesser Snow Goose population quickly overwhelmed a satiated hunter population despite liberalized harvest regulations, eventually reducing the fraction of Lesser Snow Geese being harvested each year. Consistent with the philosophy of adaptive resource management, we apply improved methods to additional years of monitoring data to evaluate the ongoing impact of harvest conservation efforts on Lesser Snow Goose harvest rates. Our previous results suggested little effect of liberalized harvest regulations on harvest rates, but our new findings suggest even less of an impact. Harvest rates have recently stabilized at ~3%, the lowest levels observed over the last 48 yr of our study. Barring adverse effects of environmental change on natural mortality or reproductive success, additional measures will need to be taken to reduce Lesser Snow Goose overabundance and their ecosystem damage.

Michael Longley and Birds

The following essay attempts to shed some light on Michael Longley’s poems about birds, which form a fairly complicated network of mutual enhancements and cross-references. Some of them are purely descriptive lyrics. Such poems are likely to have the name of a given species or a specific individual representative of that species in the title. Others make references to birds or use them for their own agenda, which often transcends the parameters of pure description. Sometimes birds perform an evocative function (“Snow Geese”), prompt the poet to explore the murky mysteries of iniquity (“The Goose”), judge human affairs from the avian vantage (“Aftermath”), or raise ecological problems (“Kestrel”). Most of the time, however, Longley is careful not to intrude upon their baffling otherness. Many of his bird poems are suffused with an aura of subtle yet suggestive eroticism, a conflation of the avian and the amorous.