Irby was educated at Rugby and joined the 90th Light Infantry on May 5th, 1854 and he left as an Ensign to be part of the Siege of Sevastopol.

He received a Turkish medal and clasp and was promoted captain by 1857 and he and his company were sent to China but the H.M. Troopship Transit was shipwrecked near Sumatra.

[2][3] Irby moved regiments to the 74th Highlanders and was sent to Gibraltar in 1868 where his enthusiasm for ornithology matured under the guidance of Lord Lilford.

[4] The book was influenced by Irby's annoyance at seeing other people publish work that did not correctly attribute the original findings.

In the second edition he was persuaded to also include the findings of Cole Verner and his friend Lord Lilford supplied fine colour pictures of birds of prey.