Orbacles is a physical manifestation of data scientists use to understand climate change. Each of the 147 bird species in the Climate Change Bird Atlas [1,2] is represented as a module – an individual birdhouse, feeder, or bath – with a hood that is sized to be proportional to the typical length and wingspan of the species [3]. The placement is consistent, so you will find one module for each species at a consistent location within each Orbacle.


Scientists often compare multiple alternatives, since the future depends in part on the choices we make today. Orbacle A shows the current situation. Orbacle B shows a low emissions scenario that reflects “high level of conservation and reduction of CO2 emissions” [2]. Orbacle C shows a high emissions scenario, assuming that “the current [fossil fuel] emissions trends continue for the next several decades” [2]. To read the data and compare the different scenarios, look for changes in color across all three Orbacles.


White represents a baseline – the current situation. If everything stayed the same in the future, then the two future Orbacles would be white, just like the current one. If the color turns orange, this means the species is expected to become less prevalent in Minnesota. (Many species decrease in prevalence in the future, some will leave Minnesota entirely.) If the color turns blue, this means the species becomes more prevalent in the future. (Many non-native species are expected to come to Minnesota for the first time.)

The Prevalence Score that drives these color changes is a number between 0 and 100. It is derived from what scientists call an area-weighted bird incidence value [2], here calculated for the area of the state of Minnesota. It can be considered to be proportional to the actual population of each species, but it might be more accurately described as how likely you would be to come across this species on a (really long) walk throughout our state. In fact, the scientific models are built upon data from the North American Breeding Bird Survey, a roadside survey conducted annually since 1966 that involves stopping periodically along predefined routes to identify the species present at each location [4].


The interactive data graphic below uses the same data and spatial arrangement as the set of three Orbacles sculptures installed in Minneapolis. Hover your mouse over each module to see how the prevelance of the species in Minnesota is expected to change over time. Clicking on a module brings up a link to additional information about the species.


The data visualized come primarily from the Climate Change Bird Atlas (A Spatial Database of 147 Bird Species of the Eastern USA) [1,2]. Typical lengths and wingspans were retrieved from the Patuxent Bird Identification Infocenter [3].

  1. Matthews, S.N., L. R. Iverson, A.M. Prasad, A. M., and M.P. Peters. 2007-ongoing. A Climate Change Atlas for 147 Bird Species of the Eastern United States [database]. https://www.nrs.fs.fed.us/atlas/bird, Northern Research Station, USDA Forest Service, Delaware, Ohio.
  2. Matthews, S. N., Iverson, L. R., Prasad, A. M. and Peters, M. P. 2011. Changes in potential habitat of 147 North American breeding bird species in response to redistribution of trees and climate following predicted climate change. Ecography, 34: no. doi: 10.1111/j.1600-0587.2010.06803.x Published online: http://onlinelibrary.wiley.com/doi/10.1111/j.1600-0587.2010.06803.x/full
  3. Gough, G.A., Sauer, J.R., Iliff, M. Patuxent Bird Identification Infocenter. 1998. Version 97.1. Patuxent Wildlife Research Center, Laurel, MD. http://www.mbr-pwrc.usgs.gov/infocenter.html
  4. Sauer, J. R., D. K. Niven, J. E. Hines, D. J. Ziolkowski, Jr, K. L. Pardieck, J. E. Fallon, and W. A. Link. 2017. The North American Breeding Bird Survey, Results and Analysis 1966 - 2015. Version 2.07.2017 USGS Patuxent Wildlife Research Center, Laurel, MD. https://www.mbr-pwrc.usgs.gov/bbs/