A precise water displacement method for estimating egg volume

Document Type

Article

Publication Date

1-1-2009

Publication Title

Journal of Field Ornithology

Volume

80

Issue

2

First Page

193

Keywords

Clapper Rail, Egg length, Egg width, Hoyt's formula, Rallus longirostris

Last Page

197

Abstract

Relationships between egg volume and an array of life-history traits have been identified for many bird species. Despite the importance of egg volume and the need for precise and accurate measurements, egg volume is usually estimated using a mathematical model that incorporates length and width measurements along with a shape variable. We developed an instrument that provides precise estimates of egg volume and can be easily used in the field. Using Clapper Rail (Rallus longirostris) eggs, we compared egg volumes measured using our instrument with estimates based on linear measurements. We found our instrument to be both precise and accurate. Compared with a method based on linear measurements of eggs, use of our instrument reduced variation in egg volume estimates by 1.6 cm3, approximately 8% of the volume of a Clapper Rail's egg. Further advantages of our technique include ease of use, increased accuracy of field-based volume estimates, and increased resolution of variation in egg volume estimates. In addition, our technique does not require postdata collection processing time and did not influence hatching success. Also, for Clapper Rails and similar species, our technique can be combined with other techniques (e.g., egg flotation) so that both egg volume and embryonic stage can be estimated at the same time. © 2009 Association of Field Ornithologists.

DOI

10.1111/j.1557-9263.2009.00222.x

ISSN

02738570

E-ISSN

15579263

Link to Full Text

Share

COinS