Mark eggs to reduce their appeal to egg collectors

Overall effectiveness category Unknown effectiveness (limited evidence)
Number of studies: 1
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How is the evidence assessed?

Effectiveness

50%
Certainty

35%
Harms

0%

Calculating overall effectiveness category

Background information and definitions

Egg collecting involves removing eggs from nests, blowing them to remove the contents and presenting the eggs in a collection. This practice can be extremely damaging for some slow-reproducing species (Ewins 1997) and is made more so by the greater value of, and demand for, rarer species’ eggs. This has led to the prohibition of egg collecting in many countries, but the practice still continues.

Marking eggs in a non-damaging way may reduce the desirability of eggs because collectors are interested in eggs for their aesthetic appeal.

Ewins, P.J. (1997) Osprey (Pandion haliaetus) populations in forested areas of North America: changes, their causes and management recommendations. Journal of Raptor Research, 31, 138–150.

Study locations

Key messages

A single before-and-after study found that marking eggs greatly increased the number of chicks fledging from six raptor nests in Australia in 1979 and 1980.

About key messages

Key messages provide a descriptive index to studies we have found that test this intervention.

Studies are not directly comparable or of equal value. When making decisions based on this evidence, you should consider factors such as study size, study design, reported metrics and relevance of the study to your situation, rather than simply counting the number of studies that support a particular interpretation.

Supporting evidence from individual studies

A small before-and-after study in the Flinders Ranges, South Australia (Olsen et al. 1982), found that twice as many young fledged from five peregrine falcon Falco peregrinus nests (12 young fledged from 16 eggs) and one wedge-tailed eagle Aquila audax nest (one chick from two eggs) in 1980, when eggs were marked with a single line drawn in black, waterproof ink, as in 1979, when no eggs were marked (6/15 and 0/2 fledged respectively).
Study and other actions tested
Referenced paper
Olsen J., Billett T. & Olsen P. (1982) A method for reducing illegal removal of eggs from raptor nests. Emu, 82.

Please cite as:

Williams, D.R., Child, M.F., Dicks, L.V., Ockendon, N., Pople, R.G., Showler, D.A., Walsh, J.C., zu Ermgassen, E.K.H.J. & Sutherland, W.J. (2020) Bird Conservation. Pages 137-281 in: W.J. Sutherland, L.V. Dicks, S.O. Petrovan & R.K. Smith (eds) What Works in Conservation 2020. Open Book Publishers, Cambridge, UK.

Where has this evidence come from?

List of journals searched by synopsis

All the journals searched for all synopses

This Action forms part of the Action Synopsis:

Bird Conservation

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