Joel Sartore / Photo Ark / European black grouse (Lyrurus tetrix tetrix) female, head portrait, Lundi Farm, Germany. Captive.

Bernard Castelein / RF - Common pochard (Aythya ferina) male, in flight over pond with reedbeds in background, Kruibeekse Polder, Belgium. April. (This image may be licensed either as rights managed or royalty free)

Joel Sartore / Photo Ark / Northern birch mouse (Sicista betulina betulina) portrait, Moscow Zoo, Russia. Captive.

Roger Powell / Red-throated loon (Gavia stellata) female on water approaching nest among reedbed, GedJnes, Kongsfjordfjellet, Finnmark, Norway. June.

Roger Powell / Red-throated loon (Gavia stellata) female, standing at nest among reedbed arranging the eggs, GedJnes, Kongsfjordfjellet, Finnmark, Norway. June.

Roger Powell / Red-throated loon (Gavia stellata) male incubating eggs on the nest among reedbeds, GedJnes, Kongsfjordfjellet, Finnmark, Norway. June.

Roger Powell / Red-throated loon (Gavia stellata) spreading wings on water, GedJnes, Kongsfjordfjellet, Finnmark, Norway. June.

Roger Powell / Red-throated loon (Gavia stellata) taking off from the breeding lochan, Gedjnes, Kongsfjordfjellet, Finnmark, Norway. June.

Roger Powell / Red-throated loon (Gavia stellata) male, running on water taking off, GedJnes, Kongsfjordfjellet, Finnmark, Norway. June.

Roger Powell / Red-throated loon (Gavia stellata) running on water taking off with reedbeds behind, GedJnes, Kongsfjordfjellet, Finnmark, Norway. June.

Roger Powell / Red-throated loons (Gavia stellata) pair engaged in parallel swimmming courtship display, GedJnes, Kongsfjordfjellet, Finnmark, Norway. June.

Roger Powell / Red-throated loon (Gavia stellata) on water, GedJnes, Kongsfjordfjellet, Finnmark, Norway. June.