Provide medicated grit for grouse
Overall effectiveness category Evidence not assessed
Number of studies: 1
Background information and definitions
Grouse commonly eat quartz grit to aid digestion of heather (Newborn & Foster 2002). This intervention involves using grit treated with medication to administer drugs, such as those used to treat parasitic worm infections, to grouse populations.
Newborn D. & Foster R. (2002) Control of parasite burdens in red grouse Lagopus lagopus scoticus through the indirect application of anthelmintics. Journal of Applied Ecology, 39, 909-914.
Supporting evidence from individual studies
A controlled experiment during 1996-2000 on two moors in northern England (Newborn & Foster 2002) found that red grouse Lagopus lagopus scoticus in an area provided with quartz grit treated with anthelmintic drugs (drugs to treat parasitic worm infections) raised between 38% and 100% more chicks than grouse in a control area (treatment areas: 4.9-7.1 chicks/hen estimated from 36 radio-tagged birds and 4.9-6.7 chicks/hen estimated from 125 birds seen on counts using pointing dogs vs control areas: 1.9-4.8 chick/hen from 36 tagged birds and 2.8-4.5 chicks/hen from 117 on dog counts) and had significantly lower levels of infection of the parasitic nematode Trichostrongylus tenuis (34% fewer worms over five years). This was despite the fact that the medicated areas did not have larger broods or higher hatching success (medicated areas: 9.6 eggs/clutch, 90% hatching success for 161 clutches; control areas: 9.4 eggs/clutch, 94% hatching rate for 153 clutches). Survival rates of adults did not vary between medicated and control areas.Study and other actions tested