Royal Australasian Ornithologists Union early 20th century called themselves 'oologists', though the distinction between the notionally scientific discipline of oology and simple egg-collecting was blurred. Identification of any but the most common and distinctive species usually entailed the collection of specimens to be made into study skins. Modern field-guides did not exist and few people could afford the massive multi-volume, lavishly illustrated, handbooks of John Gould and Gregory Mathews. However, both Archibald J. Campbell and Alfred North had produced comprehensive guides to what was known about the nests and eggs of Australian birds, with illustrations of the eggs rather than of the birds themselves,
(What Is) Love? she was dissatisfied with the circumstances, but was in "no way dissing Lopez." A mastered version of "What Is Love?" was included on the soundtrack to "The Back-up Plan" (2010), a film in which Lopez stars. "What Is Love?" was re-titled as "(What Is) Love?" and appeared on "Love?" (2011). "(What Is) Love?" was due to be released as a promotional single from "Love?" on April 26, 2011, but was "unlocked" and released four days earlier, on April 22, 2011 by through a campaign on Lopez's Facebook page. It was released in many European countries on April 25. The song