Page 166 - Hand rearing birds second

151

9

Loons

Renée Schott and Jesse Menne

Natural History

Loons occupy their own Family (Gaviidae) and Order (Gaviiformes). There are five species of
extant loons: the Common Loon (Gavia immer), the Yellow‐billed Loon (Gavia adamsii), the
Pacific Loon (Gavia pacifica), the Arctic Loon (aka Black‐throated Loon) (Gavia arctica), and the
Red‐throated Loon (Gavia stellata). All loon species are Northern hemisphere, migratory birds that
breed in or near Northern freshwater bodies but overwinter in marine environments, generally
south of where they breed. They are heavy‐bodied diving birds with legs positioned so caudally on
their body, they are largely incapable of walking on land. They prefer bodies of water that are clear
(easier to see fish), have a surface area large enough for takeoff, and minimal human interference.
Pacific and Arctic Loons require 30–50 m of open water for takeoff under calm conditions. Red‐
throated Loons need 15–40 m, depending on wind. Common Loons, and probably Yellow‐billed
Loons, require up to 200 m for takeoff, but can lift off in substantially shorter distances if taking off
into high winds. Common Loons do relatively well in human inhabited areas (Titus and VanDruff
1981; Caron and Robinson 1994); they breed closer to human populations than any other loon spe-
cies, and so are the most likely young loon to be admitted for wildlife rehabilitation. Almost all
human experience raising loons has been with Common Loons (Barr 1996; Kenow et al. 2014).
This chapter will be based on care of Common Loons, but likely much of the techniques and infor-
mation can be extrapolated to other species of loons. Hereafter, “loon” is used to imply “Common
Loon” unless otherwise noted.
Loons feed primarily on fish but will also eat insects, annelids, mollusks, amphibians, and only
rarely vegetable matter. Loons rely on stones present in their ventriculus to help them digest the
prey they swallow whole as they do not cast pellets.
Common Loons potentially live to more than 30 years old (Tischler 2011; Piper et al. 2017). It is
estimated that ~50% of Common Loon juveniles will survive to 3 years of age (Piper et al. 2012).
Loons mature at age 3 and on average obtain breeding territory around age 5. They are long‐lived,
slow to mature, and have low fecundity. Loons nest within 2 meters of water, on shore, or on other
similar areas, like a muskrat lodge (Tischler 2011). Made by both sexes, the nest is typically formed
using a collection of plant material. Nest sites are often used year‐to‐year. Loons are territorial; a
mated pair will defend an area of water (5–50 ha) from other loons. Loons may share a lake with
other loons, but they have distinct territories within the lake and nest in separate bays/areas. Loon
chicks are semi‐precocial, and swim after hatching, although they will ride on the parent’s back to

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.