Jim Brandenburg / Fire in prairie, Minnesota

Shattil & Rozinski,Shattil & Rozinski / Black bear (Ursus americanus) cub climbing a fence, Minnesota, USA, May.

Ingo Arndt / Timber Wolf (Canis lupus) running in snow, Minnesota

Ingo Arndt / Timber Wolf (Canis lupus) crossing river, Minnesota

LYNN M. STONE / Trumpeter Swans (Cygnus buccinator) with heads up after dipping to feed in shallow waters. Mississippi River, Minnesota, USA, February.

Jim Brandenburg / Thickspike Gayfeather (Liatris pycnostachya) flowering on tallgrass prairie, Crow-Hassan Park Reserve, Minnesota

Bryan and Cherry Alexander / Ice-fishing huts on Mille Laks Lake. Minnesota, USA, 1985.

Jim Brandenburg / Blue Jay (Cyanocitta cristata) pair fighting while a third watches, Minnesota

Jim Brandenburg / Sundogs, also known as mock sun, with snow field, Minnesota

Jim Brandenburg / Thickspike Gayfeather (Liatris pycnostachya) flowers with eagle-shaped cloud, Touch the Sky Northern Tallgrass Prairie National Wildlife Refuge, Minnesota

LYNN M. STONE / Trumpeter Swans (Cygnus buccinator) in winter morning mist, showing aggression during courtship behaviour, Mississippi River, Minnesota, USA, February

LYNN M. STONE / Trumpeter Swans (Cygnus buccinator) in winter morning mist, showing aggression during courtship behaviour, Mississippi River, Minnesota, USA, February