Asynchronous changes in phenology of migrating Broad‐tailed Hummingbirds and their early‐season nectar resources

Abstract

Abstract. Phenological advancements driven by climate change are especially pronounced at higher latitudes, so that migrants from lower latitudes may increasingly arrive at breeding grounds after the appearance of seasonal resources. To explore this possibility, we compared dates of first arrival of Broad-tailed Hummingbirds (Selasphorus platycercus) to dates of flowering of plants they visit for nectar. Near the southern limit of the breeding range, neither hummingbird arrival nor first flowering dates have changed significantly over the past few decades. At a nearby migration stopover site, first flowering of a major food plant has advanced, but peak flowering has not. Near the northern limit of the breeding range, first and peak flowering of early-season food plants have shifted to earlier dates, resulting in a shorter interval between appearance of first hummingbirds and first flowers. If phenological shifts continue at current rates, hummingbirds will eventually arrive at northern breeding grounds after flowering begins, which could reduce their nesting success. These results support the prediction that migratory species may experience the greatest phenological mismatches at the poleward limits of their migration. A novel hypothesis based on these results posits that the poleward limit for some species may contract toward lower latitudes under continued warming.

Hummingbird tongues are elastic micropumps

“…In addition it could also improve our understanding of broadscale ecological patterns (e.g. species range limits and competition in hummingbird assemblages [6], and phenological shifts with conservation implications [26]). …”

Ecology: Change is in the air

“…Glacier lilies in the US midwest are blooming before their hummingbird pollinators arrive 1 ; malnourished Atlantic salmon are entering Scottish waterways later 2 ; birds and plants are moving higher in the Swiss Alps 3 ; and amphibians in drought-stricken California are struggling to stay alive 4 . All over, environmental changes are forcing plants and animals to modify their survival tactics.…”

Impact of Climate Change on Flowering and Fruiting Times of Nunavut Arctic Plants

“…For each species separately, I ran a regression analysis of the flowering time records with the associated June mean temperature over the last 70 years (1946 -2015) to determine the flowering time temperature-sensitivity of each of the 23 plant species. I found great diversity in the flowering time temperature-sensitivity of the 23 species (Panchen and Gorelick, in press), and I suggested that the interspecific variation in responsiveness to climate change could lead to altered Arctic ecological community competition, pollinator interactions, and ultimately Arctic ecological community composition (Hegland et al, 2009;McKinney et al, 2012;CaraDonna et al, 2014). The flowering time temperature-sensitivity also varied within a species: for example, plants from the Nunavut archipelago (includes the Boothia and Melville Peninsulas, as well as islands north of Hudson Bay) were more temperature-sensitive than their conspecifics from mainland Nunavut farther south (includes islands with similar latitude and climate), and within the Nunavut archipelago, plants from Baffin Island were more temperature-sensitive than their conspecifics from Ellesmere Island.…”