Skip to main content Accessibility help

What colour is penguin guano?

  • W.G. Rees (a1), J.A. Brown (a1) (a2), P.T. Fretwell (a2) and P.N. Trathan (a2)

The identification and quantification of Antarctic Pygoscelis penguin colonies depends increasingly on recognition of the characteristic optical properties of guano deposits, but almost all knowledge of these properties until now has been compromised by resolution and atmospheric propagation effects. Here we present hyperspectral reflectance data in the range 350–2500 nm, collected in situ from fresh guano deposits in Pygoscelis penguin colonies on Signy Island, South Orkney Islands. The period of data collection included the transition from predominantly white guano to the pink coloration characteristic of a krill-rich diet. The main identifiable features in the spectra are a broad absorption feature centred around 550 nm, responsible for the pink coloration and identified with the pigment astaxanthin, as well as several water absorption features. Variations in these features are responsible for differentiation between spectra. From these results we propose two spectral indices suitable for use with satellite data, one of which responds to the presence of astaxanthin in the guano and the other to water. Our results do not allow us to differentiate between penguin species from their guano, but do suggest that the breeding phenology of Pygoscelis penguins could be determined from a time series of multispectral imagery.

Corresponding author
Hide All
Agnew, D. 1997. The CCAMLR ecosystem monitoring programme. Antarctic Science, 9, 235242.
Ainley, D. 2002. The Adélie penguin: bellwether of climate change. New York, NY: Columbia University Press, 310 pp.
Auerswald, L., Freier, U., Lopata, A. & Meyer, B. 2008. Physiological and morphological colour change in Antarctic krill, Euphausia superba: a field study in the Lazarev Sea. Journal of Experimental Biology, 211, 38503858.
Black, C.E. 2016. A comprehensive review of the phenology of Pygoscelis penguins. Polar Biology, 39, 405432.
Boersma, P.D. 2008. Penguins as marine sentinels. Bioscience, 58, 597607.
CCAMLR. 1992. CCAMLR ecosystem monitoring programme (CEMP) standard methods. Hobart, TAS: CCAMLR.
Cramér, H. 1999. Mathematical methods of statistics. Princeton, NJ: Princeton University Press, 592 pp.
Croxall, J. & Kirkwood, E. 1979. The distribution of penguins on the Antarctic Peninsula and islands of the Scotia Sea. Cambridge: British Antarctic Survey, 186 pp.
Dissing, B.S., Nielsen, M.E., Ersbøll, B.K. & Frosch, S. 2011. Multispectral imaging for determination of astaxanthin concentration in salmonids. PLoS ONE, 10.1371/journal.pone.0019032.
Eaton, J., Bateman, D., Hauberg, S. & Wehbring, R. 2015. GNU Octave version 4.0.0 manual: a high-level interactive language for numerical computations. Available at:
Forcada, J. & Trathan, P.N. 2009. Penguin responses to climate change in the Southern Ocean. Global Change Biology, 15, 16181630.
Fox, D. 1955. Astaxanthin in the American Flamingo. Nature, 175, 942943.
Fretwell, P.T. & Trathan, P.N. 2009. Penguins from space: faecal stains reveal the location of emperor penguin colonies. Global Ecology and Biogeography, 18, 543552.
Fretwell, P.T., Phillips, R.A., Brooke, M.D.L., Fleming, A.H. & McArthur, A. 2015. Using the unique spectral signature of guano to identify unknown seabird colonies. Remote Sensing of Environment, 156, 448456.
Heine, J.C. & Speir, T.W. 1989. Ornithogenic soils of the Cape Bird Adélie penguin rookeries, Antarctica. Polar Biology, 10, 8999.
LaRue, M.A. & Knight, J. 2014. Applications of very high-resolution imagery in the study and conservation of large predators in the Southern Ocean. Conservation Biology, 28, 17311735.
LaRue, M.A., Lynch, H.J., Lyver, P.O.B., Barton, K., Ainley, D.G., Pollard, A., Fraser, W.R. & Ballard, G. 2014. A method for estimating colony sizes of Adélie penguins using remote sensing imagery. Polar Biology, 37, 507517.
Lynch, H.J. & LaRue, M.A. 2014. First global census of the Adélie penguin. Auk, 131, 457466.
Lynch, H.J., White, R., Black, A.D. & Naveen, R. 2012. Detection, differentiation, and abundance estimation of penguin species by high-resolution satellite imagery. Polar Biology, 35, 963968.
Myrcha, A. & Tatur, A. 1991. Ecological role of the current and abandoned penguin rookeries in the land environment of the maritime Antarctic. Polish Polar Research, 12, 324.
Naveen, R., Lynch, H.J., Forrest, S., Mueller, T. & Polito, M. 2012. First direct, site-wide penguin survey at Deception Island, Antarctica, suggests significant declines in breeding chinstrap penguins. Polar Biology, 35, 18791888.
Rees, W. 2013. Physical principles of remote sensing, 3rd edition. Cambridge: Cambridge University Press, 441 pp.
Schwaller, M.R., Benninghoff, W.S. & Olson, C.E. 1984. Prospects for satellite remote-sensing of Adélie penguin rookeries. International Journal of Remote Sensing, 5, 849853.
Schwaller, M.R., Southwell, C.J. & Emmerson, L.M. 2013. Continental-scale mapping of Adélie penguin colonies from Landsat imagery. Remote Sensing of Environment, 139, 353364.
Schwaller, M.R., Olson, C.E., Ma, Z.Q., Zhu, Z.L. & Dahmer, P. 1989. A remote-sensing analysis of Adélie penguin rookeries. Remote Sensing of Environment, 28, 199206.
Southwell, C., Emmerson, L., McKinlay, J., Newbery, K., Takahashi, A., Kato, A., Barbraud, C., DeLord, K. & Weimerskirch, H. 2015. Spatially extensive standardized surveys reveal widespread, multi-decadal increase in East Antarctic Adélie penguin populations. PLoS ONE, 10.1371/journal.pone.0139877.
Trathan, P.N. 2004. Image analysis of color aerial photography to estimate penguin population size. Wildlife Society Bulletin, 10.2193/0091-7648(2004)32[332:IAOCAP]2.0.CO;2.
Trathan, P.N., García-Boroboglu, P., Boersma, D., Bost, C.-A., Crawford, R.J.M., Crossin, G.T., Cuthbert, R.J., Dann, P., Davis, L.S., de la Puente, S., Ellenberg, U., Lynch, H.J., Mattern, T., Putz, K., Seddon, P.J., Trivelpiece, W. & Wienecke, B. 2015. Pollution, habitat loss, fishing, and climate change as critical threats to penguins. Conservation Biology, 29, 3141.
Waluda, C.M., Dunn, M.J., Curtis, M.L. & Fretwell, P.T. 2014. Assessing penguin colony size and distribution using digital mapping and satellite remote sensing. Polar Biology, 37, 18491855.
Weimerskirch, H., Inchausti, P., Guinet, C. & Barbraud, C. 2003. Trends in bird and seal populations as indicators of a system shift in the Southern Ocean. Antarctic Science, 15, 249256.
Witharana, C. & Lynch, H.J. 2016. An object-based image analysis approach for detecting penguin guano in very high spatial resolution satellite images. Remote Sensing, 10.3390/rs8050375.
Woehler, E.J. & Riddle, M.J. 1998. Spatial relationships of Adélie penguin colonies: implications for assessing population changes from remote imagery. Antarctic Science, 10, 449454.
Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

Antarctic Science
  • ISSN: 0954-1020
  • EISSN: 1365-2079
  • URL: /core/journals/antarctic-science
Please enter your name
Please enter a valid email address
Who would you like to send this to? *



Altmetric attention score

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed