Water Fowl

grebes swim in a lake
Like a duck, water fowl lived along the shores of lakes and rivers and had webbed feet. Some of their fossil tracks are virtually indistinguishable from modern water birds and they may share many other characteristics as well.

NPS photo / Ken Conger

a ruler next to water fowl fossilized tracks

Gruipeda vegrandiunus is an ichnospecies that was first discovered in Denali. The species name means “small one” as the tracks are very small compared to others in the area. It is a threetoed bird with webbed feet. Uhangrichnus chuni is named after a geologic formation in South Korea and for the person who discovered the tracks. Two sizes of these tracks have been found in Denali and the feet are completely webbed.

Identification level: Ichnospecies
Gruipeda vegrandiunus and Uhangrichnus chuni have been identified to species using trace fossils alone. This ichnospecies classification is based on shape, form, and implied behavior as opposed to the specific organism that created the fossil. When attempting to identify the birds that made the tracks, they can only be called “shorebirds” and “water fowl” respectively.

size comparison showing a park ranger towering over a duck
How do I size up?- Denali water fowl ranged in size. Most would seem similar to modern ducks or even smaller. What a contrast to the large pterosaurs they were flying around!

What is for dinner?
It is likely the ancient water fowl had diets similar to modern shore birds that eat fish, aquatic plants, and invertebrates like worms and clams.

How do we know I lived in Denali?
There are so many fossil bird tracks in Denali that it may represent the largest record of bird diversity from the Late Cretaceous. Denali’s fossil bird tracks are found in ancient river and lake shoreline environments. They have three toes and some of the tracks appear to be completely webbed or have traces of webbing.

Fun Fact
Denali contains rocks from a geological formation that preserves the largest bird diversity known from the Late Cretaceous Period.

Last updated: August 15, 2016

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