Earliest of our Birds

Most "Birders" will have a view about which of the birds we know today have been in existence for the longest period of time. Some will quote the extinct Dodo and suggest that Pigeons are a quite ancient group. It's obviously a subjective question, dependent on experience and where you are in the world, but I think that the birds in the following table are likely candidates for inclusion:-

Ostrich Albatross Falcon Flamingo
Spur Fowl Herons Swift Grebe
Brush Turkeys Loon Owl Gull
Swans, Geese, Ducks Coot Stork Pigeon
Penguins Parrots

Looking at these birds the most significant factor which differentiates one group from another is size and body form. In most cases the appearance immediately identifies a bird as an Ostrich, Flamingo, Heron, Loon, Owl, Gull, Swan, Goose, Duck, Pigeon, Penguin or Parrot. As we move on to the later birds they become smaller and much more similar to one another in terms of body form.

We can however identify various characteristics, even in these earliest birds, which re-appear again and again in many of the birds of the world. Some have evolved characteristics which suit them for walking or running, others

I have started with plant eating birds which have evolved in different body forms in two different environments:-

Terrestrial Birds.

Birds which favour a terrestrial environment tend to be large and robust.

  • Ostriches are flightless and tend to stand their ground or run when danger threatens. Rhea and Emu are similar.
  • Bustards and Korhaan (body form like the Ostrich) are quite robust but are reluctant fliers and tend to stand their ground rather than run. Forested areas provide cover for birds like Cassowaries, Brush-turkey and Spurfowl. These birds still show evidence of spurs on their legs as well as head ornamentation both of which are a testament to their primitive origins. Wooded areas are also home to birds like Chachalacas, Curassows and Guans which display head ornamentation.
  • Tinamous are weak fliers, staying hidden until the last minute and then flying short distances to cover and safety.
  • Probably the most well known to "birders" is the large range of Pheasants, Francolins etc which can fly well but prefer to hide in low ground cover, only flying when flushed.

Aquatic Birds.

As with the terrestrial birds above many birds which are associated with aquatic environments are large and robust. The critical difference is that their feet facilitate swimming and diving rather than walking or running.

  • Swans, Geese, Ducks and Pelicans have webbed feet enabling them to swim and dive.
  • Coots have lobed feet which also facilitate diving.
  • Penguins have webbed feet for swimming, the feet are placed well back on the body and the wings have become flippers.
  • Loons have webbed feet but their legs are placed well back on the body making them streamlined for pursuing fish under water.
  • Gulls and Albatross have webbed feet and are surface feeders. Albatross takes fish mainly at night.
  • Cormorants have webbed feet, diving from the water surface to swim in pursuit of fish. They have a hooked tip to the beak.

The following birds are long-legged and often long-necked:-

  • Stork and Flamingo are long-legged, long-necked wading feeders.
  • Herons, Egrets and Bitterns stand out from other waders because they have long, dagger shaped beaks.
  • Herons and Egrets display a calm, confident, patient appearance as they watch for prey.
  • Bitterns are much more secretive, keeping in reed-bed cover.
  • Cranes also have dagger beaks but they are shorter than that of the Heron, Egret and Bittern.

Aerial Feeders.

  • Swifts catch insects on the wing, cling to surfaces rather than perch.
  • Frigate-bird is piratical forcing other birds to disgorge fish.

Nocturnal Hunters.

  • Owls locate prey by sound. Catch prey using talons and hooked beak.

Diurnal Hunters

  • Falcon locates prey by sight. Catches prey using talons and hooked beak.

Pigeons.

  • Originally a woodland bird. Tend to become scavengers.

Parrots.

  • Forest bird - fruit eater.

In Summary.

At some point in time, about 65 to 45 mya, the birds we now know today had evolved into Terrestrial, Aquatic and Aerial habitats the largest variety being Aquatic birds. Examples of Birds of Prey or hunters in both Diurnal and Nocturnal situations were known. Birds which were entirely Aerial feeders had become established. In forests and woodlands birds which were to become fruit eaters and scavengers were known.

Various characteristics which were to re-appear were:-

  • Use of camouflage to hide in cover.
  • Leg placement to facilitate swimming.
  • Diurnal hunters.
  • Nocturnal hunters.
  • Dagger-shaped beaks to catch prey.
  • Talons to hold prey.
  • Hooked-tip beaks to tear prey.
  • Piratical and scavenging behaviour.