Bewicks Swan
white or yellow neckband 3 digits + A/E/T
Details
| coordinator |
Peter de Vries
send e-mail
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| website | none |
| cr-birding | https://cr-birding.org/node/151 |
| animals | 485 |
| observations | 25484, of which 488 are captures |
| ringed in | 2005 to 2025 |
Guidelines for scoring fat stores in Bewick’s Swans
When observing individually marked Bewick’s swans (color-ringed or, additionally, radio-tagged), it comprises valuable information (besides notes on accompanying partner and young) to also make a standardized assessment of their fat reserves, as these reflect the condition of the individual. A large portion of the total fat reserves are stored as abdominal fat, which can be visually estimated in the field based on the abdominal profile. Initially developed for geese (Owen, 1981, Journal of Wildlife Management 45: 227-230), this technique was later applied also to the Bewick’s swan (Bowler, 1994, Ardea 82: 241-248).
Based on Bowler’s original 6-class-scale but further adapted to better fit forms of abdominal profiles as observed in the field, new revised illustrations were prepared (by G. Eichhorn & F. Mohrwinkel at NABU, Germany). Please refer to these revised illustrations and descriptions as a reference when scoring the Abdominal Profile Index (API). Additionally, you can download silhouettes, where you can draw the abdominal profile line yourself, as a practical exercise that helps familiarizing with profile differences and for recording observations in the field.
It is recommended to observe the animal for a sufficiently long period in the field, ensuring that it is in a favorable position for assessment: side-on to the observer, in a relaxed posture (not in a tense position when alarmed or pulling at food items, because contracted belly muscles may change the profile). Note that when assessing the API, the score given should always reflect the relative volume of fat stored in the abdomen, while the exact shape of the profile line is less relevant.
Example bird
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262E
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