1904 – 2004
Bibliografía (36 obras)
Moral foundations
2007
Trogons, laughing falcons, and other neotropical birds
1999
Life of the flycatcher
1997
Tales of a naturalist
Antbirds & ovenbirds
1996
The minds of birds
Orioles, blackbirds, and their kin
Origins of nature's beauty
1992
Life of the pigeon
1991
Birds asleep
1989
Life of the tanager
Helpers at birds' nests
1987
A naturalist amid tropical splendor
Life ascending
1985
Life of the woodpecker
Birds of tropical America
1983
Nature through tropical windows
New studies of tropical American birds
1981
A naturalist on a tropical farm
1980
Aves de Costa Rica
The imperative call
1979
1977
A bird watcher's adventures in tropical America
Parent birds and their young
1976
The life of the hummingbird
1973
Studies of tropical American birds
1972
A naturalist in Costa Rica
1971
The golden core of religion
1970
Life histories of Central American highland birds
1967
The quest of the divine
1956
Life histories of Central American birds
1954
Ahimsa on the farm
1951
Problems in Milpa Agriculture
1950
Anatomy of leaf of banana, Musa sapientum L. var. Hort. Gros Michel
1928
