On this page we will post corrections and updates to The Sibley Guide to Bird Life & Behavior. Most of the changes listed below will appear in the latest printing of the book. In most cases, these changes correct minor errors or clarify unclear statements. New information (e.g., the latest taxonomic changes made by the AOU; new information on Accidentals, etc.) will be reserved for a second edition of the book.
Corrections and clarifications
page 21 – Aerodynamics section: Since the book’s publication, several problems have been identified in this section, primarily because the aerodynamics of bird flight is exceedingly complex. The main error is the suggestion that the Bernoulli effect explained in the 2nd paragraph under Lift and Drag, is sufficient to explain the lift required for birds to get airborne. Other sources of lift are involved in bird flight. Due to the complexity of the topic we have chosen not to alter this section until we are able to get alternative text reviewed by researchers knowledgeable about the latest advances in the study of avian flight.
page 22 – column 1, 1st full paragraph: The last sentence should read: “The shape of a bird’s wing in cross section is similar to that of some airplane wings.”
page 23 – column 2, under Wing shape, Wing-loading, and Aspect Ratio: 1st paragraph should read “Lift is produced as a wing deflects air downward, and the amount of air that is deflected – and thus the amount of lift produced – depends on both the wing’s area and shape.”
page 24 – column 1, 1st paragraph: The last sentence should end: “… will have a heavy wing-loading.”
page 24 – column 1, 4th paragraph: The third sentence should read: “Increasing aspect ratio, for a particular wing area, reduces drag because it lessens the influence of the turbulence that is generated at the wing tips.”
page 53 – column 2, 1st full paragraph: “… and its daytime energy needs by as much as 200 to 300 percent.” should read “… and its daytime energy needs by more than 100 percent.”
page 95 – column 1: In the last paragraph of the section about chaparral, this habitat is confounded with coastal sage scrub. This paragraph has been replaced with the following text: ” Another shrubland habitat – coastal sage scrub – also occurs along the southern California coast, typically at lower elevations and drier sites than chaparral. This habitat is home to the threatened California Gnatcatcher (Polioptila californica), and its extent has been greatly reduced as cities along the coast expand.”
page 141 – caption at top of page should read “All procellariids have relatively high wing-loading and must achieve and maintain high airspeeds to get, and stay, airborne. Because it is difficult to flap their long, narrow wings rapidly enough to attain these critical speeds, members of this family must run across the surface of the water when taking off in calm conditions.”
page 214 – column 1, 1st paragraph under Reversed Sexual Size Dimorphism: “… and why it is the reverse of the usual pattern in the animal world …” should read “… and why it is the reverse of the usual pattern in the avian world …”.
page 172 – column 2, 2nd paragraph: “Active feeding … balance.” should read “Active feeding may serve to flush prey and extending a wing may help birds maintain balance.”
page 217 – column 2, top paragraph: The sentence “Like a vulture, … in flight.” should read “Like a vulture, the Zone-tailed Hawk holds its wings above its body in a shallow “V” and rocks from side to side in flight”.
page 262 – column 1, under Eggs: “… often produce a second brood.” should read “… often produce two or more broods.”
page 298 – column 2, 2nd paragraph under Skimmers: The discussion of wing morphology in relation to aerodynamics in this paragraph is misleading. Specifically wing-loading does not necessarily influence aerodynamic stability.
page 299 – column 2, top: The comparison of wing morphology of different jaegers in relation to aerodynamics in this paragraph in misleading. This text has been rewritten as: “… lemmings, during the Arctic summer, although the two species use different methods to capture these prey. Long-tailed Jaegers typically hover-hunt for lemmings from the air, whereas the less agile Pomarine Jaegers frequently use their large bills to dig the rodents out of their subterranean hiding places.”
page 319 – introductory paragraph: For clarity, “Two of the more familiar … Mourning Dove …” has been changed to “Two of the more familiar members of the family are the introduced Rock Dove (C. livia), which is well known as the common, city-dwelling “pigeon”, and the abundant Mourning Dove …”.
page 339 – introductory paragraph: “… in virtually all habitats …” should read “… in virtually all terrestrial habitats …”
page 379 – illustration of woodpecker tongue and hyoid bone: the lower illustration is incorrect, the tongue muscle simply retracts into its sheath and does not droop down in a large loop as shown.
page 383 – column 1, 1st paragraph: “Species normally nest in…” should read “This species normally nests in…”
page 383 – column 2, 2nd complete paragraph: Ivory-billed Woodpecker has not yet been declared officially extinct by the U.S. Fish and Wildlife Service, although it is thought to have been extirpated in the United States. This sentence has been replaced with the following text: “Despite rumors, there has not been a confirmed sighting of this species within the United States in decades. A major expedition in Louisiana in 2002 was unable to find any evidence that the species persists.”
page 407 – last paragraph under Conservation: the reference to “Black-headed Vireo” should be “Blue-headed Vireo”
page 417 – illustration of lark foot, caption should begin: “The feet of larks are characterized by an elongate hind claw, which …”
page 434 – introductory paragraph: “… where they move both up and down tree trunks, unlike creepers and woodpeckers, which move only up.” should read “… where they frequently move both up and down tree trunks, unlike creepers and woodpeckers, which typically move only up.”
page 502 – column 1, 1st paragraph: “Spector suggests … territorial defense.” should read “Spector suggests that primary songs are all-purpose long-distance signals and extended songs are used in intense close encounters with either sex.”
page 565 – Airfoil, definition should read: “A structure around which air flows, creating lift; such as a bird’s wing.”
page 565 – Barbules, definition should read: “Projections from the barbs of a feather that overlap and interlock with a system of hooks and ridges.”
page 567 – Culmen, definition should read; “The central midline ridge of the maxilla.”
page 569 – Home range, definition should read: “The area that an animal uses in the course of its daily activities. Not necessarily defended.”
page 570 – Kleptoparasitism, first sentence of definition should read: “Strategy of stealing items, such as food or nest materials, from other individuals. ”
page 570 – Mast, definition should read: “Nuts and other large fruits that accumulate on the forest floor.”
Many thanks to the following people for their helpful comments: David Blue, Miyoko Chu, Sandy DeSimone, Susan Herrick, Jerome Jackson, Jef Raskin, David Spector, and Ray Telfair.