Theres an urgent need to understand these mechanisms to make accurate projections of species responses to CC in tropical hyperdiverse regions.
..aside from the inherent interest in species ranges which naturalists of all shapes interact with daily (and that we have so much still to learn about!)

Why do tests like this matter?!
Understanding elevational ranges, allows us to understand elevational changes..

We know that tropical montane birds are shifting their ranges upslope.. (e.g. www.pnas.org/doi/abs/10.1...)

The answer appears to lie in habitat preference -

lower elevation (dominant) Catharus mexicanus, preferentially chooses open broadleaf forest and avoids fern dominated forest, excluding the higher elevation (subordinate) C.frantzii to habitats it doesn't want to occupy..

For Nightingale-Thrushes, an interaction between competition and habitat shape their elevational ranges.

The interaction between them is asymmetric (the norm in birds) - with the lower elevation species, dominant over its higher elevation counterpart.

So WHY NOT go higher up, if you can?

..with that info, we can test each hypothesis..
The upshot here is that thermal physiology has no bearing on where species CAN physically live (2x BMR suggested as the physiological 'ceiling' for species) - our species live comfortably within this.
So if not physiology, then what?

Then..
3. Measuring thermal physiology - what energetic cost to cold exposure does a species incur at different elevations?
4. Measuring microhabitat at every survey site
5. Experimentally testing how competition looks between species onlinelibrary.wiley.com/doi/full/10....

So i wanted to get mechanistic, and measure each of these variables on species and test them in unison, which meant:
1. Establishing abundance patterns across elevation by lots of point counts
2. Characterising the thermal environment birds experience across elevation..

3 key explanations-
1. Physiology (its too cold/hot at different elevations for a species to persist)
2. Competition between species limits distribution
3. Habitat (an ecological preference/specialism limits the range)..

There is nice work on each, but nothing pulling them together...

It was (still is..) wild to me that you can hike through the range edges of species.
Higher up = common, lower down = absent (or vice versa)

But what causes this?!
and why do species occur where they do?!
our understanding of what limits species ranges is still remarkably incomplete..

Pleased to contribute some long(ish..) term data from Honduras as part of BioTIME 2.0: a terrific dataset ripe for all sorts of questions! onlinelibrary.wiley.com/doi/10.1111/...
Also another wake up call as to the massive biological data gaps across equatorial Africa (and the tropics in general)..

The old one from swaro ELs is a perfect fit. I got rid of the new one and replaced with the old one immediately!

Liquid whistles of Swainson’s Warbler.. fast becoming one of my favourite birds of the south eastern bottomland forests of the US..

Anyone reading this know anything about this paper in Bill ABC?! Would love to hear more if so!

If you want the best-worst conceptual figure this is my all time fave from bioone.org/journals/ard... I dont understand it but I love it

Big fan of the (new?) aberrant plumage tag on Macauley library - some enjoyable perusing of some avian weirdos tagging some of my own images..
search.macaulaylibrary.org/catalog?tag=...

Not quite..
We don't actually know that the calls of the birds referred to here (in several other locations in the western Congo Basin), are Itombwe/Prigogine's Nightjar!
They are presumed, and a looot of questions remain, and it could indeed be an sp nov...
web.archive.org/web/20220302...

HUGE thanks go to the many fieldstaff that have contributed to this effort.
Stay tuned for much more from our programme!
Are you a bander and interested in joining in the field?
these data?
tropical montane birds?
contact me! 5/5
#ornithology @ibisjournal.bsky.social

We're now one of few tropical sites with a decade+ of constant effort/banding data!
Such long term projects are essential in understanding fundamental ecology of tropical birds, as well as change..
e.g. this 10yr old Spotted Woodcreeper-left, and an immature (FCF) Slate-coloured Solitaire 4/5

..our programme here is a slooww burning, long- investment of work, unfortunately there is no fast track to understanding tropical forests, and their denizens..
I wrote about this a long time ago in @btobirds.bsky.social
'Lifecycle' but now these data are finally seeing daylight! 3/5