When I Consider!

“Evidence From Biology”

The loon is designed quite differently than almost all other birds. While the bodies of most birds are designed as light and aerodynamic as possible, the loon’s body is heavier, allowing it to sink until only its head is above water. It controls its ability to float by inflating or deflating tiny air sacs under its skin. When flying at high altitude, where the air is thin, the loon can conserve oxygen by limiting the flow of blood to its massive leg muscles.

Red-throated Loon (Gavia stellata) by Daves BirdingPix

The loon also has a perfectly developed reflex which limits the flow of blood to its wings and digestive tract during underwater dives. This allows the loon to hold its breath for long periods of time. Although an average dive lasts about 40 seconds, three-minute dives that cover 300-400 yards are quite common. Astounding dives have been documented where loons have held their breath for as long as 15 minutes while swimming underwater for over 2 miles.

Both common sense and the laws of probability tell us that these many unique abilities could not have evolved by chance processes such as random mutations. The loon could not have developed its unique diving ability in some step-at-a-time manner. It would have starved to death long before it caught its first fish. The system had to work perfectly from the beginning.”

Great Northern Loon (Gavia immer) by J Fenton

Character Sketches, Vol III. p.49

For thou art great, and doest wondrous things: thou art God alone. (Psalms 86:10 KJV)

From September 18, A Closer Look at the Evidence, by Richard and Tina Kleiss
More – “When I Consider!”

Lee’s Additions:

“any of five species of diving birds constituting the genus Gavia, family Gaviidae. Loons were formerly included, along with the grebes, to which they bear a superficial resemblance, in the order Colymbiformes, but they are considered to constitute their own separate order. Loons range in length from 60 to 90 cm (2 to 3 feet). Characteristics include a strong tapered bill, small pointed wings, webs between the front three toes, and legs placed far back on the body, which makes walking awkward. Loons have thick plumage that is mainly black or gray above and white below. During the breeding season the dorsal plumage is patterned with white markings, except in the red-throated loon (Gavia stellata), which during the summer is distinguished by a reddish brown throat patch. In winter the red-throated loon develops white speckling on the back, while the other species lose these markings.” (Britannica Online)
“Loons are excellent swimmers, using their feet to propel themselves above and under water and their wings for assistance. Because their feet are far back on the body, loons are poorly adapted to moving on land. They usually avoid going onto land, except when nesting.

Pacific Loon (Gavia pacifica) by Ian

All loons are decent fliers, though the larger species have some difficulty taking off and thus must swim into the wind to pick up enough velocity to become airborne. Only the Red-throated Diver (G. stellata) can take off from land. Once airborne, their considerable stamina allows them to migrate long distances southwards in winter, where they reside in coastal waters. Loons can live as long as 30 years.”

“The loons are the size of a large duck or small goose, which they somewhat resemble in shape when swimming. Like in these but unlike in coots (which are Rallidae) and grebes (Colymbiformes), their toes are connected by webbing. They may be confused even more readily with cormorants (Phalacrocoracidae), which are not too distant relatives of divers and like them are heaviset birds whose bellies – unlike those of ducks and geese – are submerged when swimming. Flying loons resemble a plump goose with a seagull’s wings, which seem quite small in proportion to the bulky body. They hold their head slightly pointing upwards during swimming, less so than cormorants do, and in flight they let the head decidedly droop down compared to all other aquatic birds of comparable habitus.

Males and females do not differ in plumage. Males are a bit larger on average, but usually this is only conspicuous when directly comparing the two parents. Their plumage is largely patterned black-and-white in summer, with grey on the head and neck in some species, and a white belly in all of them. This resembles many sea-ducks (Merginae) a lot – notably the smaller goldeneyes (Bucephala) – but is distinct from most cormorants which rarely have white feathers, and if so usually as large rounded patches rather than delicate patterns. All species of divers have a spear-shaped bill.”(Wikipedia)

See Also:
Peterson’s Field Guide Video Series on the Common Loon (Now the Great Northern Loon)
Gaviidae – Loons
Loon from Wikipedia
An interesting article in The Wilson Bulletin dated September 1947 – “The Deep Diving of the Loon and Old-Squaw and its Mechanism“