With respect to the means by which this strange and odious instinct was acquired, if it were of great importance for the young cuckoo, as is probably the case, to receive as much food as possible soon after birth, I can see no special difficulty in its having gradually acquired, during successive generations, the blind desire, the strength, and structure necessary for the work of ejection; for those cuckoos which had such habits and structure best developed would be the most securely reared.
Instintu bitxi eta gorrotagarri hau erdiesteko bitartekoei dagokienez, baldin kukumearentzat garrantzi handiko izan bazen, ziurrenik izan ere izan zen moduan, jaio eta berehala ahalik jatekorik gehien hartzea, ez diot zailtasun berezirik ikusten kukukumeak mailaka, belaunaldiz belaunaldi, jaurtikitze lanerako behar diren grina itsu, indar eta egitura erdietsi izanari; izan ere, aztura eta egitura horiek garatuen zituzten kukukumeak izanen ziren segurtasun handienaz haziko zirenak.