Bad for birds, good for squirrels

Here’s a nice video I stumbled upon about Lisa Aubry’s group’s work at Utah State Uni. Climate change is having a positive effect on uinta ground squirrels, allowing them to fatten-up and attain weights higher than those recorded historically. This population is survival limited, and survival probability is higher the fatter the squirrels are, so abundance responds positively to this climate change. I can’t handle … Continue reading Bad for birds, good for squirrels

On phenology and bet-hedging

Environmental fluctuations may cause natural selection to favor phenologies that systematically deviate from the resource maximizing strategy. In temporally variable environments, because fitness is taken from the geometric (not arithmetic) mean growth rate (Gillespie, 1974), this permits the evolution of bet-hedging strategies (Simons, 2011), which are strategies that maximises total fitness by reducing temporal variation at the cost of arithmetic mean fitness (Ripa et al. … Continue reading On phenology and bet-hedging

The interesting case of blue tits in France

I’ve recently been reading about a several decade long study centred around blue tits in France and on the island of Corsica. The work is being carried out by a group in the evolutionary ecology unit at the Centre D’Ecologie Fonctionnelle & Evolutive and it crosses over all kinds of interesting areas of ecology and evolution. The mainland study area is dominated by deciduous habitat … Continue reading The interesting case of blue tits in France

Are caterpillars really that important?

Typically the the kinds of models that I’m interested in assume that fledging rate is very dependent upon a phenological match between nestlings’ peak food requirements and the peak in caterpillar abundance. However I recently read a study by Cholewa and Wesołowski (2011; Acta Ornithologica) pointing out that, while literature shows that blue tits and marsh tits are indeed strongly dependent upon this food type, … Continue reading Are caterpillars really that important?

Do birds sometimes respond to warming temperatures by delaying their phenology?

Climate change has caused an advance in phenological events in many species. In migratory birds, the effects of warming flow causally up the trophic levels. For example, warmer temperatures lead to earlier plant phenology (e.g. budding), which leads to earlier peaks in the abundance of foods (e.g. insect larva) that are important to raising nestlings, which puts pressure upon birds to advance their own breeding … Continue reading Do birds sometimes respond to warming temperatures by delaying their phenology?

What is the relationship between lay date, mismatch, and overall fitness for migratory birds?

Food availability at the breeding site often has a peaked temporal profile such that food is very abundant for a short period of time. Therefore, migratory birds must also time their arrival such that there is adequate time to gather the resources needed for egg production, and time their nesting and laying so that nestlings can take advantage of these food peaks. Failure to do … Continue reading What is the relationship between lay date, mismatch, and overall fitness for migratory birds?