David Tipling / Red-rumped swallow (Cecropis daurica) near Zamora, Spain, June.

Staffan Widstrand / Wild Wonders of China / Striated swallow (Cecropis striolata) breeding on top of a modern lightbulb, Tangjiahe National Nature Reserve, Qingchuan County, Sichuan province, China

Mathias Schaef/ BIA / Red-rumped Swallow (Cecropis daurica), Lesvos, Greece

Mathias Schaef/ BIA / Red-rumped Swallow (Cecropis daurica), Lesvos, Greece

Mathias Schaef/ BIA / Red-rumped Swallow (Cecropis daurica) flying, Lesvos, Greece

Mathias Schaef/ BIA / Red-rumped Swallow (Cecropis daurica), Gaziantep, Turkey

Hermann Brehm / Lesser striped swallow (Hirundo abyssinica) collecting mud for nest building, Little Kwara, Botswana June

Hermann Brehm / Lesser striped swallow (Hirundo abyssinica) collecting mud from nest building, Little Kwara, Botswana June

Staffan Widstrand / Wild Wonders of China / Striated swallow (Cecropis striolata) nest on top of a modern lightbulb, Tangjiahe National Nature Reserve, Sichuan province, China. April.

Markus Varesvuo / Red-rumped Swallow (Hirundo / Cecropis daurica) perched on barbed wire fencing, Israel, March

Markus Varesvuo / Red-rumped Swallow (Hirundo / Cecropis daurica) in flight, Israel, March

Markus Varesvuo / Red-rumped Swallow (Hirundo / Cecropis daurica) resting on stem of vegetation, Israel, March

Mike Wilkes / Lesser striped swallow (Cecropis abyssinica unitatis) on branch singing, Serengeti, Tanzania.

Peter Waechtershaeuser / Red-rumped Swallow (Cecropis daurica), India

Christine Jung / Red-breasted Swallow (Cecropis semirufa), Etosha Nationalpark, Oshikoto, Namibia

Ralph Martin / Red-rumped Swallow (Cecropis daurica) carrying mud to build nest, Croatia

Cyril Ruoso / Red-rumped Swallow (Cecropis daurica) collecting mud to build a nest, Rwanda

Fabrice Cahez / Red-rumped Swallow (Cecropis daurica) portrait. Extramadura, Spain, May.

Florian Möllers / Lesser Striped Swallow (Hirundo / Cecropis abyssinica) perched, Budongo Forest Reserve, Masindi, Uganda, Africa.

Roger Powell / Red rumped swallow (Cecropis saurica) perched on a barbed wire fence during rain on migration, Evora, Portugal

Roger Powell / Red rumped swallow (Cecropis daurica) perched on barbed wire during rain on migration, Evora, Portugal

ASHISH & SHANTHI CHANDOLA / Red rumped swallow at nesting colony (Cecropis daurica) Ranganathitoo NP, Mysore, India

Rolf Nussbaumer / Red-rumped Swallow (Hirundo daurica) collecting mud for nesting material, Samos, Greek Island, Greece. April 1994

Philippe Clement / Red rumped swallow's nest in building (Cecropis / Hirundo daurica) made of mud pellets, Spain

David Cottridge / Red rumped swallow (Cecropis daurica) collecting mud for nest building, Lesvos, Greece

David Cottridge / Red rumped swallow (Cecropis daurica) collecting mud for nest building, Lesvos, Greece

Pete Oxford / Lesser striped swallow collects mud for nest {Cecropsis abyssinica} Zanzibar, Tanzania

Pete Oxford / Lesser striped swallow in nest {Cecropsis abyssinica} Jozani forest reserve, Zanzibar, Tanzania

Mike Wilkes / Lesser striped swallow {Cecropsis abyssinica} Masai Mara GR, Kenya

David Cottridge / Red rumped swallow collects mud for nest {Cecropis daurica} Lesvos, Lesbos, Greece

DAVID TIPLING / Red rumped swallow {Hirundo daurica} perched on wire, Lesbos, Greece

Pete Oxford / Lesser striped swallow {Cecropis abyssinica} in nest against corrugated iron, Jozaniforest Reserve, Zanzibar

Peter Blackwell / Red rumped swallow {Cecropis daurica emini} Amboseli NP, Kenya

Mike Wilkes / Lesser striped swallow {Cecropsis abyssinica} Maasai Mara, Kenya, East Africa

Bernard Castelein / Lesser striped swallow (Hirundo abyssinica) Serengeti NP, Tanzania

Dietmar Nill / Red rumped swallow collecting mud {Cecropis daurica} Spain

Dietmar Nill / Red rumped swallow collecting mud for nest {Cecropis daurica} Spain

Jose B. Ruiz / Red rumped swallow flies to mud nest in building {Cecropis / Hirundo daurica} Spain

Jose B. Ruiz / Red rumped swallow collecting mud {Cecropis daurica} Spain

Eric Sohn Joo Tan/ BIA / Red-rumped Swallow (Cecropis daurica) collecting mud at puddle, Yala National Park, Sri Lanka

Nature Production / A Pair of Red-rumped Swallow {Hirundo / Cecropis daurica} looking out of the nest, Japan, June

Jose B. Ruiz / Red rumped swallow collecting mud {Cecropis daurica} Spain {Hirundo}

Jose Luis GOMEZ de FRANCISCO / Red rumped swallow (Cecropis / Hirundo daurica) collecting mud for the nest, Monfrague NP, Caceres, Spain, April

Jose Luis GOMEZ de FRANCISCO / Red rumped swallow (Cecropis / Hirundo daurica) collecting mud for its nest, Monfrague NP, Caceres, Spain, April

Richard Flack / Mosque swallow (Cecropis senegalensis) in flight carrying nesting material in beak, Makuleke Concession, northern Kruger National Park, South Africa.

Jussi Murtosaari / Ventral view of flying Red-rumped swallow (Cecropis daurica), Finland. May.

Markus Varesvuo / Red-rumped swallow (Hirundo daurica) in flight. Happy Island, China. May.