A permanent exhibit of simple black silhouettes of North and South American birds now graces the white north wall of the visitor’s center in the Imogene Powers Johnson Center for Birds and Biodiversity, home to the Cornell Lab of Ornithology.

The 120-by-40-foot mural, by Connecticut artist James Prosek, also features black retro-styled numbers next to each silhouette, suggesting a legend with species names. But Prosek purposefully left the key off the wall, as a way to force viewers to inquire or reflect on different aspects of each image.

“I want [visitors] to look at the wall first and try to enjoy the diversity of shapes and forms of these creatures without needing to know what the name of the thing is, because knowing the name of something isn’t necessarily knowing what it is,” Prosek said.

“As soon as we have a name for something it limits what it can be,” he added, though he will create a handout with names.

His mural is also a tribute to Roger Tory Peterson’s 1934 “Guide to Birds” and its endpapers, which have silhouettes of birds with numbers that match a list of names. “[Peterson] turned people into pocket naturalists,” said Prosek.

Prosek’s silhouettes are part of the lab’s 2015 centennial anniversary, which will acknowledge the lab’s long history of combining science with the visual arts. The lab has commissioned permanent installations by Maya Lin, Jane Kim and Prosek. The other two installations are pending.

“What I proposed was a tribute to the cultural side of birding and bird-watching because there is no other natural science that has such an intimate or influential presence that the amateur side of ornithology does,” Prosek said.

For Prosek, the use of silhouettes also suggests something ancient and basic in human history.

“Written language began with the reduction of forms in this way,” Prosek said, referring to early alphabets, hieroglyphs and cave painting. Birds in the sky are often visible with no more detail than a silhouette, though the stark forms convey much information, Prosek said.

The artist designed the mural on a computer over a year and a half. The lab’s only requirement was to make the birds life-size, and he worked closely with lab ornithologists to make the forms and sizes accurate. The wall itself, which has vents and doors, imposed restrictions. “Limits can give us possibility, because without a structure to start with it’s really hard to know where to begin,” Prosek said, much like how a poet may work in a strict sonnet format.

When the design was done, he printed it in sections on sheets 50 times larger than the mock-up. He taped individual sheets to the wall, over graphite paper, and traced the birds to transfer outlines onto the wall; he then brushed in the birds and habitats with black paint. Retro numbers next to each silhouette were blown up from Peterson’s guide.

The wall features 140 different bird species and 170 total birds in five habitats: tropical rainforest, Sonoran desert, Northeast forest, Everglade mangrove estuary and Atlantic coast.

Sources for the birds included references to famous bird artists Peterson, John James Audubon and Francis Lee Jaques, among others, Google images, books and paintings.

“It would have been very hard to do this 20 or 30 years ago, without digital rendering and without all the access to images we have now,” Prosek said. “I like the idea that the piece was designed on a computer and then hand painted. It’s digital and then back to analog.”

Prosek is widely known for his art, documentaries and books about fish, most recently “Trout of the World: Revised and Updated” (2013) and “Eels” (2010). He is writing a book about how we name and order the natural world.