Study
Avian olfactory navigation: its empirical foundation and conceptual state
Wallraff, Hans G.
Animal Behaviour, 2004
Assesses whether the atmosphere carries stable enough spatial gradients of trace compounds to support a navigational map, alongside the behavioural evidence from olfactory deprivation.
- Studied in
- Columba livia
- Sample size
- review of the experimental record and of atmospheric trace-gas measurements
Measured atmospheric trace-gas ratios do vary spatially in a sufficiently orderly way to be usable in principle, and the behavioural record is consistent with birds learning such gradients at the home loft.
What it means
The authors' reading, and ours. Where they differ, that difference is the point.
How the authors put it
An olfactory gradient map is physically plausible as well as behaviourally supported, though the specific compounds remain unidentified.
How NatureHQ reads it
Cited beside Gagliardo because it addresses the objection that matters most: the behavioural result could be real and the mechanism still impossible if the air carried no usable gradients. It argues that the air does. Which compounds is still open, and the page says so.
- Argues plausibility from atmospheric chemistry; no compound has been shown to be the one birds use.
- Pigeon-centred, and the extension to wild migrants is an inference.
What this study is used for on NatureHQ
One study can inform several subjects. Here is everywhere this one is cited.
Homing pigeons
Take away a pigeon’s sense of smell and it still homes from places it knows. Release it somewhere unfamiliar and it cannot choose a direction — which places smell in the map, not in the compass.
Smell, and how far it really works
The open sea looks featureless and does not smell featureless. Seabirds are drawn to a compound released where plankton are being eaten, and it is concentrated over seamounts and shelf edges rather than spread evenly.
Published by: Elsevier journalsPublished in an Elsevier journal.
doi.org/10.1016/j.anbehav.2003.06.007
Checked against Crossref on 2026-09-28, and they agree on the title, the authors and the year.
NatureHQ summarises research in its own words and does not reproduce published text. Reviewed 2026-09-03.