Ornithology and integrated pest management: Red‐winged BlackbirdsAgelaius phoeniceusand corn

Abstract

Red‐winged Blackbirds Agelaius phoeniceus, the most abundant bird in North America, annually destroy over 360 000 tonnes of field corn and substantial amounts of sweet corn. This loss, representing <1% of North American corn production, is localized within 8 km of wetlands where Red‐winged Blackbirds roost in late summer. Red‐winged Blackbirds are often initially attracted to corn fields to feed on insect pests during the 2–3 week period between silking and kernel development. An ideal resolution of the conflict between corn farmers and Red‐winged Blackbirds is to couple the birds' beneficial feeding habits in silking‐stage corn with management techniques to reduce subsequent damage to kernels. Once birds switch from feeding on insects to feeding on corn, protective measures to reduce damage are more critical in the early (milk) stages of kernel development than later because the damage potential is much higher at this time. Birds must eat three times more kernels at 20 days after silking than at 40 days in order to receive the same corn biomass. The use of bird‐resistant cultivars of corn, the deployment of frightening devices during the critical damage period, and the provision of alternative feeding sites are important components of an integrated management programme. The goal is to accommodate Red‐winged Blackbirds as a part of the wetland‐agricultural complex in North America.

Laboratory efficacy of an anthraquinone-based repellent for reducing bird damage to ripening corn

“…Sweet corn is typically harvested 16-20 DAS leaving a short window for damage by birds. Damage to field corn also begins during R3 but continues through the dough stage (R4) up to 30 DAS due to the delay in harvest of field corn (Dolbeer, 1990). Blackbirds are known to damage corn by slitting the husk and pecking out the contents of the exposed kernels (Dolbeer, 1980).…”

“…Blackbirds, specifically red-winged blackbirds (Agelaius phoeniceus), and common grackles (Quiscalus quiscula) are the species most commonly associated with depredation of ripening sweet and field corn (DeGrazio, 1964;Dolbeer, 1990;Woronecki et al, 1981). Within the United States damage to ripening sweet corn begins 15 days after silking (DAS) when corn kernels are in the milk stage (R3 growth stage).…”

Edge Effects on Avian Diversity and Density of Native Grass Conservation Buffers

“…Control methods of Dickcissels in these areas have contributed to the dramatic drop in population size of this species [36]. Though Red-winged Blackbirds have been implicated in crop losses [37], we did not observe any large flocks of blackbirds or crop damage caused by either Dickcissels or Red-winged Blackbirds.…”

Avian foraging behaviour in relation to provision of ecosystem services in a highland East African agroecosystem

“…The species mostly associated with crop damage were Speke's Weaver, Baglafecht Weaver and Speckled Mousebird, particularly where farmers grew monocultures of wheat, oat, maize and Brassica vegetables (kale and cabbages). Although this small number of bird species does cause economic damage at the local scale, most studies suggest that, at the ecosystem level, the services provided by birds are overwhelmingly positive (Sekercioglu 2006, Whelan et al 2008 and that some birds that cause crop damage can, at other stages of crop growth serve to control pests (Dolbeer 1990, Wenny et al 2011. In this study, for example, Baglafecht and Speke's Weavers also take invertebrate prey (Hockey et al 2005, Kissling et al 2007 and Speckled Mousebirds were also observed taking weed plant parts.…”