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Sea­Ducks

Michele Goodman

Natural History

Sea duck species comprise the tribe “Mergini” within the family Anatidae, which includes eiders,
scoters, mergansers, goldeneyes (including Bufflehead), and a few monotypic species including
the Harlequin Duck, the Long‐tailed Duck, and the extinct Labrador Duck. For detailed accounts
on the natural history of North American waterfowl, see Baldassarre (2014), and for international
species accounts, see Kear (2005). Sea ducks, as expected, spend much of their time on the water
and can be poorly adapted to walking on land. Many species do not reach sexual maturity until 2
or 3 years of age. Within the group, there is considerable diversity relating to habitat selection and
use as well as dietary preferences. All species are primarily carnivorous, feeding on benthic inver-
tebrates and other aquatic animals. Mergansers are nearly exclusively piscivorous. Sea ducks are
skilled divers, generally using their large feet to propel them underwater; some species (primarily
eiders) use their wings to paddle underwater. As a group, many sea ducks have declining popula-
tions and are the subject of interest among conservationists (Bowman et al. 2015). Captive breed-
ing efforts are ongoing for threatened species like Steller’s Eider, Scaly‐sided Merganser, and
Brazilian Merganser while investigating the possibility for future reintroductions.

­ Record­Keeping­and Duckling­Identification

Private aviculturists and zoological institutions should strive to keep detailed records on the water-
fowl in their care including info on parentage, egg‐lay dates, egg weights and dimensions, fertility
data, hatch dates, and hatch weights. Much of this information is not available to wildlife rehabili-
tators, but the location of stranding and details of care prior to admittance should be obtained from
the person relinquishing the animal. Paper or digital records should be kept on each animal with
daily progress notes. Chick weights should be recorded twice daily until the ducklings are eating
sufficiently to maintain weight. The collection of frequent weights is a valuable tool for imple-
menting a nutritional support program, discussed later. See Appendix 1 for a sample wildlife reha-
bilitation animal record and Chapter 1 for information regarding record keeping.
While it is often desirable to identify each bird individually, this can be challenging with rapidly
growing waterfowl. Cable ties (or zip ties) are useful for individual bird identification as they are
inexpensive and come in a wide array of colors. The use of different colors makes identification of

Hand-Rearing Birds, Second Edition. Edited by Rebecca S. Duerr and Laurie J. Gage.
© 2020 John Wiley & Sons, Inc. Published 2020 by John Wiley & Sons, Inc.