The human eye: a cross-section. Coloured line engraving by G. Kirtland after R. Hooper, 1803. https://www.rawpixel.com/image/13951717/image-paper-cross-artFree Image from public domain licenseSet of fish illustrations found in Fishes of North America https://www.rawpixel.com/image/266352/premium-illustration-psd-pike-fish-from-game-birds-and-fishes-north-america-dentonView licenseMaskalonge fish png vintage sticker, transparent background https://www.rawpixel.com/image/9345572/png-sticker-vintageView licenseMaskalonge (Lucius Ohiensis; Kirtland) illustrated by Sherman F. Denton (1856-1937) from Game Birds and Fishes of North… https://www.rawpixel.com/image/266377/premium-illustration-psd-america-american-ancientView licenseKirtland's warbler singing in Grayling, MIKirtland's warbler. Photo By Jim Hudgins/USFWS. Original public domain image from… https://www.rawpixel.com/image/4028940/photo-image-plant-leaf-birdFree Image from public domain licenseKirtland's WarblerPhoto by Joel Trick/USFWS. Original public domain image from Flickr https://www.rawpixel.com/image/4028717/photo-image-tree-woods-birdFree Image from public domain licenseKirtland's WarblerKirtland's warbler in Wisconsin. The Kirtland's warbler is an endangered species that nests in jack pine… https://www.rawpixel.com/image/4028833/photo-image-tree-woods-birdFree Image from public domain licenseKirtland's Warbler in MichiganPhoto by Jim Hudgins/USFWS. Original public domain image from Flickr https://www.rawpixel.com/image/4028890/photo-image-bird-summer-natureFree Image from public domain licenseThe human ear: a diagram showing the parts of the inner and outer ear. Coloured line engraving drawn by G. Kirtland in 1801… https://www.rawpixel.com/image/13966843/image-paper-cartoon-artFree Image from public domain licenseKirtland's Warbler in MichiganPhoto by Jim Hudgins/USFWS. Original public domain image from Flickr https://www.rawpixel.com/image/4028911/photo-image-tree-plant-birdFree Image from public domain licenseKirtland's Warbler in MichiganThis Kirtland's warbler is banded and wears a geo-tracker with an antenna. These tools help us… https://www.rawpixel.com/image/4028629/photo-image-bird-animalFree Image from public domain licenseThe human eye: a cross-section. Coloured line engraving by G. Kirtland after R. Hooper, 1803. https://www.rawpixel.com/image/13962763/image-paper-person-bookFree Image from public domain licenseMaskalonge (Lucius Ohiensis; Kirtland). Digitally enhanced from our own 1913 Portfolio Edition of Game Birds and Fishes of… https://www.rawpixel.com/image/266337/free-illustration-image-fish-north-america-dentonFree Image from public domain licenseKirtland's Warbler in MichiganPhoto by Jim Hudgins/USFWS. Original public domain image from Flickr https://www.rawpixel.com/image/4029040/photo-image-bird-animalFree Image from public domain licenseTwo lateral views of the human heart. Coloured engraving by G. Kirtland, 1806. https://www.rawpixel.com/image/14009946/two-lateral-views-the-human-heart-coloured-engraving-kirtland-1806Free Image from public domain licenseThe bloodvessels of the arm and hand. Coloured engraving by G. Kirtland, 1804. https://www.rawpixel.com/image/13978121/the-bloodvessels-the-arm-and-hand-coloured-engraving-kirtland-1804Free Image from public domain license30 plates of the small pox and cow pox drawn from nature / [by Capt. Gold, R.A.] Published [and engraved] by G.K. https://www.rawpixel.com/image/14016020/image-cow-hand-personFree Image from public domain licenseKirtland's Warbler in MichiganPhoto by Jim Hudgins/USFWS. Original public domain image from Flickr https://www.rawpixel.com/image/4028415/photo-image-bird-animalFree Image from public domain licenseHuron-Manistee - RA - 001Kirtlands Warbler. Original public domain image from Flickr https://www.rawpixel.com/image/4034966/photo-image-tree-plant-birdFree Image from public domain licenseThe bloodvessels of the thigh: front and back views. Coloured engraving by G. Kirtland, 1805. https://www.rawpixel.com/image/13988533/image-wood-public-domain-human-anatomyFree Image from public domain license