Crane-like Birds

Think of me like a crane - Like modern-day cranes, these prehistoric birds likely used Alaska as a seasonal nesting ground and migrated south in winter. This migration corridor is still used by sandhill cranes today. It is likely that some ancient birds, like their modern descendants, used Alaska as a land bridge between Asia and North America.

NPS Photo / Tim Rains

 

Magnoavipes (“big bird track”) Denaliensis (named for the mountain that is the “high one”) is an icnnospecies that has so far only been found in Denali. This large bird was similar to a heron and had three toes. Ignortornis mcconnelli was similar to a sandpiper. More than 30 Aquatilavipes swiboldae tracks have been found so far in Denali.

Identification Level: Icnospecies
Magnoavipes denaliensis, Ignotornis mcconnelli, and Aquatilavipes swiboldae have been identified to the species level of trace fossil (“ichnospecies”). This is a classification 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 “crane-like”.

 

What is for dinner?
Circular dimple marks found next to fossilized crane-like bird tracks suggest these birds probed the mud with their narrow bills to hunt for worms, larvae, and other invertebrates. Invertebrate fossil burrows found nearby also help to confirm these food sources

How do we know I lived in Denali?
Several hundred fossil bird tracks have been found in Denali and currently represent the northernmost bird tracks discovered from this time. Some tracks are even associated with dinosaur footprints. The variety of bird trace fossils found in Denali suggests that there was significant bird biodiversity in the northern polar region during Cretaceous times.

 

How do I size up - Some of these birds were as small as a sparrow, while others were 30% larger than a modern great blue heron!

Fun Fact
While studying a section of well-preserved fossilized birds tracks in Denali, paleontologist Tony Fiorillo noticed a set of tracks that were different from the rest. They were very large, and unique enough to qualify as a new prehistoric ichnospecies with the name Magnovipes denaliensis.