Mowing roadside verges

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

Effectiveness

30%
Certainty

30%
Harms

9%

Calculating overall effectiveness category

Background information and definitions

Roadside verges could potentially act as a valuable nesting or foraging habitat for many species of birds, but can become overgrown with rank vegetation. Mowing, therefore, may increase the value of this habitat.

Alternatively, conservationists may want to limit the number of birds using roads verges, to reduce the risk of collisions with vehicles.

Study locations

Key messages

A single replicated, controlled study in the USA found that more ducks nested on unmown roadside verges, but that over four years, nesting success on unmown verges fell to below that on mown verges.

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 replicated, controlled trial in 1969-72 in North Dakota, USA (Voorhees & Cassel 1980), found that more ducks nested in unmown than mown road verges (although this difference was not significant in 1972). However, nesting success remained between 40-60% in mowed strips, whereas it fell from >70% to <30% in unmown strips due to an increase in mammalian nest predation. Alternate mowed and unmown 1.6 km strips of roadside vegetation were compared along 37km of Interstate 94. The 23 mowed strips (totalling 123 ha) were mown once in autumn. Six duck species nested over the four years: blue-winged teal Anas discors, mallard A. platyrhynchos, gadwall A. strepera, northern shoveler A. clypeata, pintail A. acuta and lesser scaup Aythya affinis.
Study and other actions tested
Referenced paper
Voorhees L.D. & Cassel J.F. (1980) Highway right-of-way: mowing versus succession as related to duck nesting. Journal of Wildlife Management, 44, 155-163.

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
Sowing roadside verges Action Link	No evidence found (no assessment)	0	Synopsis Link
Scare or otherwise deter birds from airports Action Link	Likely to be beneficial	2	Synopsis Link
Mowing roadside verges Action Link	Unknown effectiveness (limited evidence)	1	Synopsis Link