Tag Archives: migration

The Waze

Migration – that big annual event where some animals ‘pack up and ship out’ when the season starts to turn and better pastures are to be found elsewhere. Although we may not really understand how bird migration routes work, we do know that they seem to be ‘pre-programmed’ – individuals don’t typically veer off of the designated route (although some individuals might get blown off course and a bit turned around).

That being said, long-term observation of Richard’s pipits has revealed that (at least some of them) have exchanged their usual north-south migration route in and out of Russia for an east-west alternative. Although we might not be 100% sure what caused these individuals to recalculate their routes, it does open the door for some more questioning with regards to the flexibility and ‘reprogrammability’ of these long-standing migration routes.

You can read the research article at the link below:

A new westward migration route in an Asian passerine bird


It’s Not How You Get There, But When

When migrating, animals like the great white pelican have to walk the fine line between saving time and saving energy. (Image Credit: Ray in ManilaCC BY 2.0, Image Cropped).

Landscape-dependent time versus energy optimisations in pelicans migrating through a large ecological barrier (2019) Efrat et al., Functional Ecology, https://dx.doi.org/10.1111/1365-2435.13426

The Crux

We have all seen the amazing scenes in nature documentaries of the great seasonal migrations undertaken by many different species on this planet. By migrating between two different habitats, migrating animals are thought to maximize both how many resources they have access to, and to minimize their exposure to harsh environmental conditions.

Despite these benefits gained by migrating animals, there are risks associated with these seasonal, long-distance travel events. Migrating animals, like the great white pelican (Pelecanus onocrotalus), have to decide what is better: traveling for a shorter distance or using less energy by taking a less strenuous – but longer – path. Today’s authors tracked the great white pelican during its seasonal migration over the Sahara to study how these birds made decisions about their travel.
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The Motivation Behind Migration

Species like this red-crowned crane perform yearly migrations, but how do they weigh up the costs and benefits? (Image Credit: Alistair Rae, CC BY-SA 2.0, Image Cropped)

Where the wild birds go: explaining the differences in migratory destinations across terrestrial bird species (2018) Somveille, Manica & Rodrigues. Ecography, 42, p. 225-236.

The Crux

Migratory birds make up a huge chunk of the world’s bird life, yet there are still a lot of gaps in our knowledge concerning why they migrate to the areas they do. There’s a variety of potential benefits to migration, from remaining within a comfortable temperature range or a preferred habitat, to gaining access to areas that have a surplus in resources, to escaping competition with resident species. However, migration also results in increased mortality due to the amount of energy it takes. This week’s study tried to analyse the drivers of migration, and what trade-offs were made between migration’s potential benefits and costs.

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