2017-10-01 Sanctuary Asia

Warbler Special

Unsolved Prehistoric Mystery

Sanctuary | Natural History

The Yellowstone National Park in the U.S.A is an active supervolcano. It last erupted 6,40,000 years ago and it is believed that

the next eruption could be anytime now.

Did You Know?

The Kirtland’s Warblers’ story of near-extinction and

unprecedented revival is the stuff of legend. First identifi ed in

1951, this warbler is a habitat specialist and an extreme one

at that! It only occupies patches of forests cleared by wildfi res

comprising jack pine Pinus banksiana that stand one to fi ve

metres tall. The wildfi res must be of a particular intensity that

aids pine seed germination. For this reason, it is often referred

to as the ‘bird of fi re’. Habitat shrinkage, the species’ rigid

preference of young pines and open clearings along with a

deadly invasion by Brown-headed Cowbirds pushed Kirtland’s

Warbler numbers to a record low of less than 200 singing

males in the early 1970s.

After the threats to the warbler were identifi ed (one of the

fi rst persons to identify the cowbird parasitism threat was

a suspected murderer!), a wave of inspirational conservation

action that controlled and replicated the effects of wildfi res,

cowbird trapping, awareness and education initiatives,

plus regular surveys, saw a welcome revival of the species.

The numbers of singing males was believed to have risen

to 2,365 by 2015 according to the IUCN Red List of

Threatened Species.

Even before the Cambrian ‘explosion’ or period, about 545

million years ago, when most known animal groups fi rst emerged on

the planet, there was a mystery creature lurking in the depths of the

primordial ocean. At the turn of the present millennium, in the early

2000s, a fossil bed in Newfoundland was discovered replete with

fossils of these mysterious organisms. They called them rangeomorphs

and found that they belonged to the Ediacaran period some 635-542

million years ago. They bore complex structures, much like a feather

with central stems sprouting fractal (self-repeating) branches and were

soft-bodied. They might have anchored themselves to the ocean bed by

anchor discs or embedded themselves in the mud. There are indications

that they had a mouth or gut, or for that matter some complex organs

along the lines of existing animals. The fossils bear quite a striking

resemblance to modern-day fern fronds, but are not related to plants at

all. Rangeomorphs lived in the depths of the sea, with some growing

up to two metres in length. At these depths, even light was unable to

penetrate to trigger photosynthesis. How they acquired the necessary

nutrients to survive is still a puzzle. Though the existence of these

creatures has been now known for a good 50 years or more, experts

are still at a loss to explain what they might have been or how they fi t

into the tree of animal life on the planet. Rangeomorphs aren’t the only

mysterious Ediacarans known to science, but are undoubtedly one of

the most charismatic and iconic!

Most of the world's population of the Kirtland's

Warbler Setophaga kirtlandii is limited to the state of

Michigan in the U.S.A.

A cast of the rangeomorph Charnia masoni.

Discovered in England in 1957, it helped

establish the age of rangeomorph fossils

as Precambrian.

The warblers of North America New York,D. Appleton & Company,1907.

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