Action: Mark eggs to reduce their appeal to egg collectors
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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.
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.
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).