Buried and frozen in permafrost near the village of Belaya Gora in north-eastern Siberia, the bird was discovered by local fossil ivory hunters, who passed it on to a team of experts, including Nicolas Dussex and Love Dalén from the Swedish Museum of Natural History, for testing.
Radiocarbon dating revealed the bird lived around 46,000 years ago, and genetic analysis identified it as a horned lark (Eremophila alpestris), according to a paper published Friday in the journal Communications Biology.
Dalén told CNN that research showed the bird may be an ancestor to two subspecies of lark alive today, one in northern Russia and the other on the Mongolian steppe.
"This finding implies that the climatic changes that took place at the end of the last Ice Age led to formation of new subspecies," he said.
The bird was found in north-eastern Siberia at a site which also contained other frozen specimens.
The preservation of the bird is explained in large part by the cold of the permafrost, explained Dussex, but this specimen is in extraordinarily good condition.
"The fact that such a small and fragile specimen was near intact also suggests that dirt/mud must have been deposited gradually, or at least that the ground was relatively stable so that the bird's carcass was preserved in a state very close to its time of death," said Dussex.