My colleagues at National Audubon have just released a detailed analysis of the response of birds in North America to climate change you can read the full report here

A lot of my past research has been in the field of biogeography and changes in avian distribution, so I find this work very exciting and compelling. 

The Audubon team analyzed 40 years of data from the Christmas Bird Count to look at changes in bird distribution over this time period. There’s almost too much in this report to summarize succinctly, but here are some of the highlights:

  • Over half of the 305 species studied showed significant northward movement in their winter distributions.
  • These species moved an average of 35 miles north, while many moved over 100 miles north.
  • Significant shifts in distribution inland, away from coastal areas, were also found.
  • When landbirds are broken out by broad habitat types, woodland birds moved farther north than shrubland birds and generalists.
  • Grassland birds did not show a significant northward shift.
  • The authors report several pieces of evidence consistent with these changes being caused by global warming, including a correlation of annual movements with annual temperatures, more species moving north than south, and birds found only in southern states increasing in numbers.

What does this work tell us? 

It provides more clear evidence of the effects of global warming on the distribution of biodiversity (in this case, wintering birds) the canaries seem to be doing their job. 

It begins to call into question the effectiveness of our current network of refuges, parks and other protected areas for birds — they might not be in the right places, if bird distributions continue to change. 

The fact that certain groups, such as grassland birds, did not respond indicates that there is concern for the future impacts on some species. 

However, this should not be viewed as completely negative.  Many regions will see an increase in overall species diversity and some species formerly rare in some states will become more common. 

Climate change is an urgent matter that we must all understand.  As the work from Audubon indicates, the changes are occurring in our own states, towns and backyards you can study this yourself by keeping good records of what is in and around your neighborhood. 

For some other suggestions on climate change and what to do about it, check here.

(Image: Canary. Source: Jessi Bryan via Creative Commons.)

If you believe in the work we’re doing, please lend a hand.


  1. Hi Dave, I guess a key question is whether these range shifts lead to range expansions or contractions. What percentage of birds (and which species, the threatened ones or the ones that were relatively safe) suffer from these range shifts and which ones benefit? My guess — without knowing much about US birds — is that the ecological specialists with small ranges that were already threatened are most severely impacted by these climate-induced range shifts. Does that make sense?

  2. Great question from my colleague Erik. Yes, I think its absolutely true that the specialists and small-range species will be far more negatively impacted than generalists or species with large ranges.

    However, the one thing you have to remember about this work is that it applies to species from relatively high latitudes in the northern hemisphere in the winter season. You probably don’t have to be a rocket ornithologist to guess that many/most of these species are limited by climate (=cold temperatures) at the northern edge of their distributions. So, while a northward shift is what we predict with climate change, I’m not sure that the precise conservation implications can be determined yet, without complete analyses across all the seasons. –DM

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