John Shaw / Yellow warbler (Setophaga petechia aureola) on lava rocks. Isabela Island, Galapagos. May.

David Tipling / Spotted flycatcher (Muscicapa striata) in song North Norfolk, England, UK. May

Karine Aigner / Kirtland's warbler (Setophaga kirtlandii) sitting in tree in Jack Pine habitat. Michigan, USA. July.

Karine Aigner / Kirtland's warbler (Setophaga kirtlandii) male carrying food for young, Michigan, USA. July.

Karine Aigner / Kirtland's warbler (Setophaga kirtlandii) sitting on Jack Pine carrying food for her young, Michigan, USA, July.

Karine Aigner / Kirtland's warbler (Setophaga kirtlandii) male with nano tag, sitting on Jack pine collecting prey for young.

Karine Aigner / Kirtland's warbler (Setophaga kirtlandii) female in jack pine carrying food for young. Michigan, USA, July.

Karine Aigner / Kirtland's warbler (Setophaga kirtlandii) female in Jack pine habitat bringing food to her nest, Michigan, USA, July.

Karine Aigner / Kirtland's warbler (Setophaga kirtlandii) nano tagged male sitting in Jack pine, Michigan, USA, July.

Karine Aigner / Kirtland's warbler (Setophaga kirtlandii) male singing perched in Jack pine near nest. Michigan, USA, July.

Karine Aigner / Map of Kirtland's warbler (Setophaga kirtlandii) nests drawn by researcher, in Jack pine forest habitat. Michigan, USA, July 2017.

Karine Aigner / Portrait of a female Kirtland's warbler (Setophaga kirtlandii) a Jack pine tree. Michigan, USA, July 2017.