Sven Zacek / White-tailed sea eagle (Haliaeetus albicilla) flying over frost and snow covered forest. Tartumaa, Southern Estonia. January 2011.

Sven Zacek / Ural owl (Strix uralensis) female on nest, male landing with twig in beak. Tartumaa, Southern Estonia. April.

Sven Zacek / Ural owl (Strix uralensis) male presenting prey to nesting mate. Tartumaa, Southern Estonia. April.

Sven Zacek / Ural owl (Strix uralensis) female feeding at nest on rodent prey presented by mate. Tartumaa, Southern Estonia. April.

Sven Zacek / Ural owl (Strix uralensis) female on the nest with nestling hidden under wing. Tartumaa, Southern Estonia. April.

Sven Zacek / Ural owl (Strix uralensis) female stretching wings whilst perched in Spruce (Picea sp) tree. Tartumaa, Southern Estonia. May.

Sven Zacek / Ural owl (Strix uralensis) female and nestling on nest in tree stump. Tartumaa, Southern Estonia. May.

Sven Zacek / Mist over bog with conifers in pre-dawn light. Endla Nature Reserve, Jogevamaa, Central Estonia. June 2016.

Sven Zacek / Roe deer (Capreolus capreolus) young buck, portrait. Karula National Park, Valgamaa, Southern Estonia. June.

Sven Zacek / Beaver (Castor fiber) felling a Birch (Betula sp) tree for winter supplies. Tartumaa, Southern Estonia. November.

Sven Zacek / Frozen bog pool system, aerial view. Endla Nature Reserve, Jogevamaa, Central Estonia. December 2016.

Sven Zacek / Ural owl (Strix uralensis) female on nest after snowfall. Tartumaa, Southern Estonia. March.