|
|
Continued from Call Sound and Breeding of the Loon or Diver
Prehistoric species of Loons
in Fossils
The Loons are a very old group of birds. While the
oldest fossils which can reliably be assigned to this group originate from
the Miocene epoch (5.3 to 23 million years ago), there are far older finds,
whose actual affiliation to the Loons is however disputed.
Of these are the oldest of a species from the Cretaceous
period (65 million to 145 million years ago) known as Neogaeornis wetzeli,
of which however only fragments of a central foot bone (Tarsometatarsus)
have been excavated. Also a species thought to be from the same prehistoric
period is known as Polarornis. However, only skull fragments
of Polarornis have been found, and this species is perhaps synonymous
with Neogaeornis. Due to strong similarities with the bone
structure of modern Loons, they were considered by many scientists to be
ancestors of the current Diver or Loon. Other scientists consider
this relationship very improbable and see in Neogaeornis a Mesozoic (65
million to 245 million years ago) water bird, which developed similar characteristics
in convergent evolution as the Loons.
From the Eocene eopch (34 million to 56 million
years ago) and the Oligocene epoch (23 million to 34 million years ago)
the prehistoric species Colymboides and Gaviella have been
discovered. These prehistoric inhabitants of Europe and North America
could represent very early representatives of the Gaviiformes.
|
|
|
Human Effects and Relationships
The peoples of far northern countries have maintained
a relationship for a long time with these birds. The Inuit hunt Loons and
make clothing from their skins and feathers. This moderate hunt has never
endangered the existence of the birds. In Scotland it was considered as
bad Omen to hear the territorial call of a Loon as it crosses a lake.
This name of Loon rather than Diver is is used
particularly in North America. In Scotland it is applied to the Great
Northern Diver (also known as the Common Loon). The family is known
as Divers in Great Britain. The designation loon probably comes from the
old word "lomr", which is related to the German word "lahm" which means
"lame" or "sluggish", and could have referred to the bird's clumsy movements
whilst ashore.
|
|
The Common Loon is the national bird of Canada
and is depicted on the canadian 1 dollar coin. As a result the coin
is known in Canada by the slang name of looney.
None of the Loons are threatened species.
Unfortunately, the fact that they live in remote areas with difficult access
prevents a clear trend of the population to be developed. However,
reductions in the populations of all five species have been recorded, these
reductions being caused by human influences in the arctic ecological system.
Destruction of banks, contamination of waters and the use of fishing nets,
in which the birds can get caught are all responsible. In North America
it has been established that whole populations of Common Loons are loaded
with toxic levels of mercury which they have built up from eating fish
which have contained this chemical.
The Loons are losing considerable areas adapted
to their nesting. The increase in tourism in lake areas for recreational
activities or sports results in many Loons being scared away. Fortunately,
the existence and creation of reservoirs, partially reduce these losses,
having the effect of creating areas inaccessible to every human activity.
|
|
|
