Mark Hamblin / 2020VISION / Great tit (Parus major) taking mealworm from person's hand, Pembrokeshire Coast National Park, Wales, UK, May.

Markus Varesvuo / Blue Tits (Paris caereleus) two feeding on red berries, Uto Finland October

Andy Rouse / 2020VISION / Blue Tit (Cyanistes / Parus caeruleus) perched on lichen-covered twig. Wales, UK, February. Did you know? The front of a Blue tit's head glows brightly under UV light, which is used by females to choo...

Andy Rouse / 2020VISION / Blue Tit (Cyanistes / Parus caeruleus) perched on lichen-covered twig. Wales, UK, February.

Mark Hamblin / 2020VISION / Great tit (Parus major) perched on branch in snow, Scotland, UK, December

Mark Hamblin / 2020VISION / Two Blue tit (Parus caeruleus) adults in winter, perched on twig with frozen crab apples, Scotland, UK, December 2010

Mark Hamblin / 2020VISION / Adult Robin (Erithacus rubecula) and adult Blue tit (Parus caeruleus) in winter, perched on twig with frozen crab apples, Scotland, UK, December 2010

Loic Poidevin / Blue Tit (Parus caeruleus) perched on mossy branch. Breton Marsh, French Atlantic Coast, November.

Stefan Huwiler / Blue Tit (Parus caeruleus) adult perched on a blooming Forsythia (Forsythia intermedia). Zug, Switzerland, Europe, March.

Stefan Huwiler / Blue Tit (Parus caeruleus) adult in flight. Zug, Switzerland, Europe, February.

Hermann Brehm / Blue Tit (Parus caeruleus) on Guelder Rose branch with red berries. Bavaria, Germany, December.

Hermann Brehm / Great Tit (Parus major) in flight. Bavaria, Germany, December.

Andy Rouse / Blue Tit (Cyanistes caeruleus) perched on snow covered Fir tree (Abies) branch, in a garden, Wales, UK December

Andy Rouse / Blue Tit (Cyanistes caeruleus) perched on snow covered Fir tree (Abies) branch, in a garden, Wales, UK December

Andy Rouse / Blue Tit (Cyanistes caeruleus) perched on snow covered Fir tree (Abies) branch, in a garden, Wales, UK December

Paul Hobson / Blue tit (Parus caeruleus) flying in position to land, South Yorkshire, England, UK. March.

Paul Hobson / Blue tit (Parus caeruleus) in flight, Peak District, England, UK. March.

Stephen Dalton / Blue tits (Parus caeruleus) feeding at nut feeder, Great tit (Parus major) flying to feeder, UK

Stephen Dalton / Blue tits (Parus caeruleus) feeding at nut feeder, Long tailed tit (Aegithalos caudatus) flying to feeder, UK

Stephen Dalton / Blue tits (Parus caeruleus) feeding at nut feeder, Great tit (Parus major) flying to feeder, UK

David Kjaer / Flock of Blue tits (Parus caeruleus) and Great tit (Parus major) on Niger seed feeder, Gloucestershire, England

Gary K. Smith / Blue tit (Parus caeruleus) perching amongst crab apples, UK, November

Stephen Dalton / Collection of bird feeders in garden, with Greenfinches (Carduelis chloris) and Great tits (Parus major) UK

Stephen Dalton / Blue tit (Parus caeruleus) in flight carrying insect prey. England, UK

Stephen Dalton / Blue tit (Parus caeruleus) flying to bird-feeder, UK

Peter Lewis / Great Tit (Parus major) perching on lichen covered twig, New Forest, Hampshire, England

Andy Rouse / Great tit (Parus major) perched on branch, UK

Andy Rouse / Blue Tit (Parus caeruleus) perched in snow, Wales, UK, January

Andy Rouse / Blue Tit (Parus caeruleus) perched in snow, Wales, UK, January

Andy Rouse / Blue Tit (Parus caeruleus) perched in snow, Wales, UK, January

Andy Rouse / Blue tit (Parus caeruleus) perched in snow, Wales, UK (non-ex) January

Andy Rouse / Blue tit (Parus caeruleus) perched in snow, Wales, UK (non-ex) January

Alan Williams / Blue tit (Parus caeruleus) perched on twig with catkins, Essex, UK, February

Alan Williams / Blue tit (Parus caeruleus) calling, perched on blossom covered twig, Essex, UK, March

Andy Sands / Blue tit (Parus caeruleus) perched among Pussy willows, West Sussex, England, UK

Andy Sands / Blue tit (Parus caeruleus) perched among Pussy willow, West Sussex, England, UK

Ross Hoddinott / Blue tit {Parus caeruleus} on branch, Cornwall. UK

Ross Hoddinott / Blue tit {Parus caeruleus} on branch, Cornwall. UK

Ross Hoddinott / Blue tit {Parus caeruleus} with hazel catkins, Cornwall. UK

Ross Hoddinott / Blue tit {Parus caeruleus} on branch, Cornwall. UK

Ross Hoddinott / Blue tit {Parus caeruleus} on branch, Cornwall. UK

Kim Taylor / Blue tit (Parus caeruleus) brings food to begging chicks in nest, UK

Kim Taylor / Common swift {Apus apus} nestling. Captive, UK

Kim Taylor / Great tit nest {Parus major} with young chicks begging for food, beaks open. Captive, UK.

David Tipling / Red Squirrel {Sciurus vulgaris} and Coal Tit {Parus ater} on garden nut feeder, UK.

David Tipling / Garden birds including Blue Tits {Parus caeruleus} + Nuthatch {Sitta europaea} on bird table, UK.

Dave Watts / Two Great tits with willow catkins in snow, France {Parus major}

Kim Taylor / Blue tit {Parus caeruleus} fledgling, portrait. Captive, UK

Kim Taylor / Great Tit (Parus major) flying off with a peanut. UK, Digital composite

Colin Varndell / Blue tit brings caterpillar to young in nestbox {Parus caeruleus} UK

Colin Varndell / Great tit amongst blossom {Parus major} UK. Not available for Greetings Cards or Notelets until October 2016

WILLIAM OSBORN / Blue tit on lichen covered perch, UK

WILLIAM OSBORN / Great Tit (Parus major) female perched on branch. Wiltshire, England

WILLIAM OSBORN / Male Great tit (Parus major). England, UK, Europe

Mike Wilkes / Great tit perched in hawthorn tree, winter, England

Bengt Lundberg / Great tit brings food to nine hungry week-old chicks in nestbox, Sweden {Parus major} Sweden

Hans Christoph Kappel / Blue tit flying, Germany

WILLIAM OSBORN / Blue tit on lichen covered perch (Parus caeruleus) UK

WILLIAM OSBORN / Blue Tit portrait in spring (Parus caeruleus) Wiltshire, UK. perched in flowering sallow.

Peter Cairns / 2020VISION / Great tit (Parus major) perched on lichen covered branch, with falling snow, Scotland, UK, December.

Juan Manuel Borrero / Illustration of Great Tit (Parus major), native to Eurasia. Pencil and watercolor painting.

David Woodfall / Great Tit (Parus major) with mealworm on outstretched hand. Radnorshire Wildlife Trust Nature Reserve, Wales, UK, June.

Ben Hall / 2020VISION / Blue tit (Parus caeruleus) on feeder with man watching with binoculars in background, Poynton, Cheshire, England, UK, May. Property released.

Ben Hall / 2020VISION / Two Blue tits (Parus caeruleus) on feeder with man in background watching through house window with binoculars, Poynton, Cheshire, England, UK, May. Property released.

Mark Hamblin / 2020VISION / Great tit (Parus major) perched on person's foot, Pembrokeshire Coast National Park, Wales, UK, May.

Danny Green / Coal Tit (Periparus / Parus ater) perched with lichen. Scotland, February.

Markus Varesvuo / Blue Tit (Paris caereleus) hanging below red berries on which it has been feeding, Uto Finland November

Markus Varesvuo / Blue Tit (Paris caereleus) perched above red berries, Uto Finland October

Markus Varesvuo / Blue tits (Paris caereleus) two feeding on red berries, Uto Finland October

Peter Cairns / Blue tit (Parus caeruleus) in winter, Cairngorms National Park, Scotland, December

David Woodfall / Pip Amos, nature reserve Warden with Blue Tit (Parus caerulus) coming to his hand to feed on meal worms, Gilfach Nature Reserve, Radnorshire Wildlife Trust, Powys, Wales, UK May 2012

David Woodfall / Great Tit (Parus major) on branch of flowering Crab Apple (Malus sylvestris) Gilfach Nature Reserve, Radnorshire Wildlife Trust, Powys, Wales, UK May

David Pattyn / Great tit (Parus major) in flight, Oisterwijk, The Netherlands, February

Philippe Clement / Great spotted woodpecker juvenile (Dendrocopos major), Eurasian collared dove (Streptopelia decaocto), Blue tit (Parus caeruleus) and Great tit (Parus major) eating peanuts from bird feeder on balcony...

Fabrice Cahez / Red squirrel (Sciurus vulgaris) eating nut, with Great tit (Parus major) in the background watching, Allier, Auvergne, France, March

Fabrice Cahez / Red squirrel (Sciurus vulgaris) eating hazelnut, with Great tit (Parus major) in the background watching, Allier, Auvergne, France, March

Ernie Janes / Blue tit (Parus caeruleus) perched on footpath sign, UK, March.

Wild Wonders of Europe / Préau / Man looking at Great tit (Parus major) caught in mist net for ringing, in allotment, Grande-Synthe, Dunkirk, France, September 2010, model released

Wild Wonders of Europe / Préau / Great tit (Parus major) caught in mist net for ringing with a man removing another bird behind, in allotment, Grande-Synthe, Dunkirk, France, September 2010, model released

Wild Wonders of Europe / Préau / Great tit (Parus major) caught in mist net for ringing with a man behind, in allotment, Grande-Synthe, Dunkirk, France, September 2010, model released

Wild Wonders of Europe / Préau / Man measuring Blue tit (Parus caeruleus) wing length, caught in net in allotment, Grande-Synthe, Dunkirk, France, September 2010, model released

Wild Wonders of Europe / Préau / Man holding Great tit (Parus major) while writing notes, birds caught in net for ringing, in an allotment, Grande-Synthe, Dunkirk, France, September 2010, model released

Michel Poinsignon / Blue tit (Parus caeruleus) perched on branch in winter, Lorraine, France.

Michel Poinsignon / Great tit (Parus major) flying flying from nest carrying faecal pellet, Lorraine, France, March.

Michel Poinsignon / Great tit (Parus major) flying from nest, Lorraine, France, March.

Michel Poinsignon / Great tit (Parus major) flying to nest with caterpillar prey, Lorraine, France, March.

Michel Poinsignon / Great tit (Parus major) flying to nest with caterpillar prey, Lorraine, France, March.

Michel Poinsignon / Great tit (Parus major) flying to nest with caterpillar prey, Lorraine, France, March.

Michel Poinsignon / Great tit (Parus major) flying to nest with prey, Lorraine, France, March.

Michel Poinsignon / Great tit (Parus major) perched on larch (Larix) branch in winter, Lorraine, France, March.

Michel Poinsignon / Blue tit (Parus caeruleus) perched on branch in winter, Lorraine, France, January.

Michel Poinsignon / Blue tit (Parus caeruleus) perched on Dog rose (Rosa canina) branch in winter, Lorraine, France, January.

Michel Poinsignon / Blue tit (Parus caeruleus) perched on larch (Larix) branch in winter, Lorraine, France, January.

Michel Poinsignon / Blue tit (Parus caeruleus) perched with aggressive posture on mossy branch in winter, Lorraine, France, January.

Mark Hamblin / 2020VISION / Blue tit (Parus caeruleus) adult in flight about to land to small branch, Scotland, UK, December

Mark Hamblin / 2020VISION / Great tit (Parus major) perched on branch in snow, Scotland, UK, December