Skip to main content
Dryad

Steinhardt Museum Israeli bird morphology

Data files

Oct 09, 2022 version files 636.72 KB

Abstract

Morphological museum data for Israeli birds, including all individuals used for the analyses in Dubiner & Meiri (2022)

Aim: Body size decline has been proposed as a universal response to global warming, but this is often questioned. We describe and characterize recent morphological changes in the avifauna of Israel as a whole, and test several hypotheses regarding their cause.

Location: Israel

Time period: 1950-2020

Major taxa studied: Aves.

Methods: We analyzed the morphology of 7,981 museum specimens. For each of the 106 species we calculated the rate of change in mass, head and body length, wing length, and approximated relative surface area, over time and as a function of temperature anomaly (the difference between temperatures in a given year and the interannual average). We used phylogenetic mixed models (PGLMM) to determine trends and their relation to species’ ecology.

Results: Over the last seventy years there have been consistent changes through time in mass, length, and surface-area-to-volume. Mass declined by 18.3%, length increased by 5.1%, and surface area-to-volume increased by 28.9%. The increases in the ratio of surface area-to-volume through time corresponds to a 12.2% increase per °C of warming. Conversely, wing length changes were few and inconsistent. Most species changed in either mass or length, but seldom in both. The effect of rising temperature on morphology was roughly an order of magnitude stronger than the effect of a comparable geographic difference in habitat temperature. Changes were modulated by migratory habits but not explained by human-commensalism or diet.

Main conclusions: Mass decrease and length increase are widespread, both leading to higher relative surface area. Results conform with predicted responses to global warming, but not with any of our other tested hypotheses. If warming is indeed the driver of these changes, the diverging responses observed between different species may represent different solutions to solve a common problem.