Access

You are not currently logged in.

Access your personal account or get JSTOR access through your library or other institution:

login

Log in to your personal account or through your institution.

If You Use a Screen Reader

This content is available through Read Online (Free) program, which relies on page scans. Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.

The Use of Grit in Pipits, Especially the American Pipit (El Uso de Arenas en el Género Anthus Especialmente en Anthus rubescens)

N. A. M. Verbeek
Journal of Field Ornithology
Vol. 65, No. 4 (Autumn, 1994), pp. 498-503
Published by: Wiley on behalf of Association of Field Ornithologists
Stable URL: http://www.jstor.org/stable/20065860
Page Count: 6
  • Read Online (Free)
  • Subscribe ($19.50)
  • Cite this Item
Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
The Use of Grit in Pipits, Especially the American Pipit (El Uso de Arenas en el Género Anthus Especialmente en Anthus rubescens)
Preview not available

Abstract

It appears that both adult and nestling pipits (Anthus spp.) use grit for the mechanical breakdown of seeds and insects. Pipits in temperate regions have larger amounts of seed in their diets during fall and winter than during the summer, and apparently take more grit then than during the summer to help grind the seeds. Grit is also used for its mineral content, which is needed for growth and maintenance of both young and adults. Larger quantities of grit in nestlings than in adults during the summer, when the diet consists of insects, suggests that the mineral content is particularly important for nestling development. Grit may also be used for egg shell formation, but there was no significant difference in the mean quantity of grit per gizzard in both sexes of the American Pipit (Anthus rubescens). The possibility that females take grit particularly rich in calcium during egg laying could not be ascertained. Pipits thus take grit for different reasons throughout the year, and they may take it in different quantities depending on why it is needed at any one time. /// --Aparentemente tanto adultos como polluelos del género Anthus usan arenas para romper mecánicamente semillas e insectos. En regiones templadas, este género tienen mayores cantidades de semillas en su dieta durante el otoño e invierno que en el verano, y aparentemente toman más arenas que durante el verano para poder moler las semillas. Las arenas también se usan por su contenido mineral, e cual es necesario para el crecimiento y mantenimiento de jóvenes y adultos. Las cantidades de arenas en los polluelos son mayores que en los adultos durante el verano, cuando la dieta es pincipalmente de insectos, lo cual sugiere que el contenido mineral es particularmente importante para el desarrollo de los polluelos. Las arenas pueden ser usadas para la formación del cascarón del huevo, pero no se hallaron diferencias significativas en la cantidad promedio de arenas por molleja en ambos sexos de Anthus rubescens. La posibilidad de que hembras tomen arenas particulamente ricas en calcio mientras están poniendo no se pudo clarificar. El género Anthus toman arenas por diferentes razones a través del año, y puede que las tomen en diferentes cantidades dependiendo de para qué se necesitan en ese momento.

Page Thumbnails

  • Thumbnail: Page 
498
    498
  • Thumbnail: Page 
499
    499
  • Thumbnail: Page 
500
    500
  • Thumbnail: Page 
501
    501
  • Thumbnail: Page 
502
    502
  • Thumbnail: Page 
503
    503