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1/11: A few weeks ago we published a fun little study on the wing shapes of the grass parrots! I haven't talked about it much yet, so here's a little thread to walk you through the results!
the paper is here
https://onlinelibrary.wiley.com/doi/10.1111/jav.02586
the paper is here
https://onlinelibrary.wiley.com/doi/10.1111/jav.02586
2/11: Birds that fly long distances (e.g. migrants) tend to have long, pointy wings because this shape has less drag and is more efficient over distance.
Sedentary birds have rounded wings, which gives them more agility but is inefficient over long distances.
Sedentary birds have rounded wings, which gives them more agility but is inefficient over long distances.
3/11: because birds experience very strong selection for their flight style you can make good guesses about the lifestyle of poorly studied species by looking at their wing shape (long/pointy = mobile, short/round = sedentary)
4/11: grass parrots (Neophema and Neopsephotus spp.) are mostly poorly studied. I wanted to check if grass parrot wing shapes reflect what we think we know of their movement ecology. For most species, the literature only contains 'guesstimates' about their movements.
5/11: this is important because in migratory orange-bellied parrots, migration is a severe threat to the species survival. If related grass parrots are actually more migratory/mobile than previously realised, this may be important for conservation.
https://static1.squarespace.com/static/582ea0d1579fb3ef8b09706d/t/5f39c92c57da8940e9dac29c/1597622576959/Final+published.pdf
https://static1.squarespace.com/static/582ea0d1579fb3ef8b09706d/t/5f39c92c57da8940e9dac29c/1597622576959/Final+published.pdf
6/11: So i traveled across Aus (and to America!) to measure as many grass parrot museum skins as possible. i quantified 3 metrics of wing shape (pointedness, concavity and aspect ratio) and compared them across species.
7/11: i found that grass parrots overlapped in all aspects of wing shape. Whether they were supposedly migratory, nomadic or sedentary did not explain their wing shapes, nor did taxonomic relationships or the movement barriers they faced (the sea, arid habitats, woodlands).
8/11: We think that in unpredictable Australian environments, if you stay ready you don't have to get ready. If pointed wings don't disadvantage normally sedentary species, then having pointy wings may be a 'back up' for when conditions go bad and birds are forced to move.
9/11: these observations of wing shape also might explain why species normally considered sedentary (e.g. turquoise parrots) are also described as 'dispersive' and 'irruptive' in the available literature, based mostly on anecdotal observations.
10/11: but the study also shows that (as we expected), desert nomad grass parrots like the scarlet-chested have similarly shaped wings to their relatives that migrate over the sea. this supports the broader evidence that mobility selects for long pointy wings in birds.
11/11: looking at the wing shape of understudied species can reveal important ecological information that is normally very hard to collect, plus it's a way-more feasible first step than other approaches (e.g. tracking).
Plus, feathers are really cool and pretty.
Plus, feathers are really cool and pretty.
footnote: read the paper itself here https://static1.squarespace.com/static/582ea0d1579fb3ef8b09706d/t/5fc4207a173fb5383b2527b4/1606688899826/jav.02586%281%29.pdf
