Grit Use by Birds

Gionfriddo, James P.; Best, Louis B.

doi:10.1007/978-1-4757-4901-4_3

Cited by 68 publications

(76 citation statements)

References 173 publications

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“…During visual selection of grit, birds may be influenced by several grit characteristics such as size, colour, shape, surface texture and geochemical composition (Gionfriddo and Best 1999). Most of the grit found in waterfowl ranged from 0.5 to 3.0 mm in size, which was the size used in our experiments (Thomas et al 1977;Pain 1990;Mateo et al 2000a).…”

Section: Discussionmentioning

confidence: 94%

“…As for colour, we found that red grit was only consumed more than grey grit when it was not mixed with grain in the experiment in semi-captivity, although this difference was not observed in wild. There are no previous studies testing the effect of grit colour on grit selection by waterfowl, but several studies have described the colour of grit found in gizzards (Thomas et al 1977;Gionfriddo and Best 1999;Lee et al 2004;Luttik and de Snoo 2004). Just as with grit size, the colour and composition of grit ingested by waterfowl depends partly on the availability in the environment (Gionfriddo and Best 1999;Lee et al 2004).…”

Section: Discussionmentioning

confidence: 99%

“…Several characteristics of grit may influence its use by birds, such as composition, particle size, colour or shape (Gionfriddo and Best 1999). Moreover, the chemical composition of grit may help reduce Pb absorption due to the presence of calcium or phosphates (Heinz et al 2004;Dauwe et al 2006;Martinez-Haro et al 2009).…”

Section: Communicated By C Gortázarmentioning

confidence: 99%

“…Experiment 1-September-October 2007 Grit colour is important for grit selection in several bird species (Gionfriddo and Best 1999). Two types of calcareous grit (red or grey) were offered in containers with or without wheat grain in a 1:4 ratio (grit/grain, v/v).…”

Section: Experiments On Grit Ingestionmentioning

confidence: 99%

“…Gastroliths, more commonly known as grit, are used by birds to grind food in the gizzard and in some species also as a dietary supplement (Gionfriddo and Best 1999). However, this implies a risk of exposure to toxic metals depending on the geochemical composition of grit (Bendell-Young and Bendell 1999).…”

Section: Introductionmentioning

confidence: 99%

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Use of grit supplements by waterbirds: an experimental assessment of strategies to reduce lead poisoning

et al. 2010

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The ingestion of spent Pb shot due to confusion with grit or inadvertently with food particles causes Pb poisoning in a large number of waterbirds, this being one of the main causes of mortality for some species. Lead ammunition for hunting is being progressively banned in more countries, while grit supplementation has been proposed as a management measure to reduce the ingestion of deposited Pb shot. Studies of grit selection with waterfowl in semicaptivity and in the wild were undertaken to evaluate preferences in the colour and geochemical composition of grit, whether it was available dry or in water, its position within the wetland and the relationship between grit ingestion and feeding behaviour. Grit ingestion was higher when food was included in the treatments. In the absence of food, red grit was taken in higher amounts than grey in semi-captivity but not in the wild. Siliceous grit was taken in a higher amount than calcareous when offered dry, but not in water. No differences in the amount of ingested grit were found among different positions within the wetland. The number of feeding attempts in plots supplemented with grit was higher than in those without grit, although the highest numbers of feeding birds were found in plots supplemented with food. Grit ingestion in waterfowl is intimately associated with feeding behaviour. To optimize the effectiveness of grit supplementation to reduce the risk of Pb poisoning in waterfowl, calcareous and siliceous grit may be combined and applied in feeding sites or mixed with bait to attract birds.

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Section: Discussionmentioning

confidence: 94%

Section: Discussionmentioning

confidence: 99%

Section: Communicated By C Gortázarmentioning

confidence: 99%

Section: Experiments On Grit Ingestionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Use of grit supplements by waterbirds: an experimental assessment of strategies to reduce lead poisoning

et al. 2010

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Case Study: Problem Formulation Versus Making Problems for Yourself

Tannenbaum

2013

Alternative Ecological Risk Assessment

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Bird response to grit and pesticide granule characteristics: Implications for risk assessment and risk reduction

Stafford¹,

Best²

1999

Enviro Toxic and Chemistry

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Granular pesticides (insecticides and nematicides) pose a hazard for birds because of the potential for birds to ingest the granules. Avian risk from granular pesticides is currently assessed by using a U.S. Environmental Protection Agency risk index based on the acute toxicity of the pesticide, the pesticide concentration on the granules, and the number of granules available on the soil surface after application (LD50/ft2). Recent evaluations have demonstrated that avian response to pesticide granules as a source of grit also can influence exposure to pesticide granules; such information should be included in the risk assessment process. Herein we review the limitations of the current risk assessment process and summarize the extant information regarding bird response to grit and granule characteristics (i.e., granule carrier type, color, size, shape, and surface texture) and pesticide load per granule. Suggestions are made for assessing and reducing avian risk from granular pesticides by testing granular formulations against standards for various granule characteristics and by using frequency distributions of avian responses to granules. Granule characteristics selected as standards should be similar to grit used by free‐ranging birds (e.g., silica particles, earth‐tone hues). Comparisons of granular formulations against the standards would demonstrate the potential for birds to consume pesticide granules as grit, relative to naturally occurring particles. Frequency distributions constructed for grit sizes used by birds and gizzard grit counts can be used to estimate the effect of granule size and pesticide load per granule, respectively, on avian risk. Because bird response to pesticide granules is highly variable, we recommend using probabilistic approaches when assessing avian risk from pesticide granules to account for the ranges of response.

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Grit Use by Birds

Cited by 68 publications

References 173 publications

Use of grit supplements by waterbirds: an experimental assessment of strategies to reduce lead poisoning

Use of grit supplements by waterbirds: an experimental assessment of strategies to reduce lead poisoning

Case Study: Problem Formulation Versus Making Problems for Yourself

Bird response to grit and pesticide granule characteristics: Implications for risk assessment and risk reduction

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