Use coloured baits to reduce accidental mortality during predator control

Overall effectiveness category Unknown effectiveness (limited evidence)
Number of studies: 3
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How is the evidence assessed?

Effectiveness

20%
Certainty

30%
Harms

not assessed

Calculating overall effectiveness category

Background information and definitions

Most birds (unlike most mammals) are visual hunters and foragers, meaning that strangely coloured baits may not be taken as readily, and so using them during eradication programmes may reduce incidental mortality.

Study locations

Key messages

Two replicated and controlled trials in the USA found that dyed baits were consumed at significantly lower rates than control baits.
A replicated, randomised and controlled trial in Australia found no differences in consumption rates of dyed and control baits.

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 review of three replicated, controlled trials in Day County, South Dakota, USA, and another in Routt County, Colorado (Kalmbach & Welch 1946), in 1945, found that bird assemblages (mainly songbirds and doves) took a higher proportion of uncoloured grain (88% taken) than of yellow (73%) or green (23%) grain, and when uncoloured was not available, birds took more yellow (87% and 15% in two sites) than green (39% and 9%). In addition, more dead birds were found with uncoloured poison grain in their stomachs than with yellow. Very few birds were found with green grain.
Study and other actions tested
Referenced paper
Kalmbach E.R. & Welch J.F. (1946) Colored rodent baits and their value in safeguarding birds. Journal of Wildlife Management, 10, 353-360.
A replicated, randomised and controlled, ex situ experiment (Nicholls 2000) found that consumption of day-old chicks by 33 American kestrels Falco sparverius was greatly reduced by dying chicks green or blue, with no birds consuming blue-dyed chicks and two birds also avoiding green-dyed chicks. All birds reduced food intake significantly. Treating chicks with two repellents (discussed in ‘Use repellents on baits’) did not affect consumption in addition to dyeing. This study is also discussed in ‘Use aversive conditioning to reduce nest predation’.
Study and other actions tested
Referenced paper
Nicholls M.K. (2000) An evaluation of methyl anthranilate, aminoacetophenone, and unfamiliar coloration as feeding repellents to American kestrels. Journal of Raptor Research, 34, 311-318.
A replicated, randomised and controlled trial in Adelaide Zoo, South Australia (Johnston & McCarthy 2007), found that dyeing food (minced beef, fruit and ‘Wombaroo insectivore mix’ – a commercially available food mix) blue had no effect on its consumption by six captive bush stone-curlews Burhinus grallarius over a ten day period.
Study and other actions tested
Referenced paper
Johnston G. & McCarthy P. (2007) Susceptibility of Bush Stone-curlews (Burhinus grallarius) to sodium fluoroacetate (1080) poisoning. Emu, 107, 69-73.

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

Related Actions

Actions	Effectiveness	Studies	Category
Distribute poison bait for predator control using dispensers Action Link	Unknown effectiveness (limited evidence)	1	Synopsis Link
Use repellents on baits for predator control Action Link	Unknown effectiveness (limited evidence)	2	Synopsis Link
Use coloured baits to reduce accidental mortality during predator control Action Link	Unknown effectiveness (limited evidence)	3	Synopsis Link