2 Within the Neognathae there are also two basal lineages: Galloanserae (gamebirds and waterfowl) and Neoaves (all others). This means that the gamebirds and waterfowl must be placed next in the list (after ratites and tinamous); this was recently done in the AOU checklist (2002). Whether gamebirds (megapodes through quail) or waterfowl (screamers through ducks) are listed next is a matter of style. Dickinson (2003) puts the gamebirds first but AOU and SACC put the waterfowl first, and this fits better with the traditional arrangement (as in HBW). As noted in footnote 1, I now follow Clements' updated sequence throughout.

3 Splitting the Magpie-Goose as a separate family is a Sibley-Ahlquist (1990) innovation based on DNA hybridization; they also split the Whistling-Ducks [Dendrocygnidae] as a family. Dickinson (2003) elevates Magpie-Goose to family status but not the Whistling-Ducks; this was supported by Livesey (1997). SACC and AOU also do not elevate the Whistling-Ducks (at least for now).

4 Dickinson (2003) and AOU (1998) consider turkeys and grouse to be subfamilies of Phasianidae, as the biochemical evidence shows these lineages are embedded within the larger pheasant/partridge assemblage (e.g., Dimcheff et al. 2002). In prior lists I had followed HBW in retaining each group as a 'traditional' family, each of which is easily recognized and each of which is a monophyletic group. Now I have followed the recent evidence, and merge turkeys and grouse into the Phasianidae. I have given them separate 'subfamily' web pages, though, for convenience.

5 Grebes and flamingos are each others closest relatives; IOC, AOU, SACC all agree.

6 Christidis & Boles (2008) split the storm-petrels into two families: Hydrobatidae (northern storm-petrels) and Oceanitidae (southern storm-petrels). Most others (e.g., SACC) consider these two lineages to be subfamilies. The Christidis & Boles (2008) approach relied heavily on Nunn & Stanley (1998) and Penhallurick & Wink (2004), which argued that the storm-petrels were not monophyletic when compared to albatrosses (Diomedeidae). Penhallurick & Wink (2004) has been the subject to compelling criticism (Rheindt & Austin 2005), and the entire system of attempting to date divergence is flawed (Graur & Martin 2004). Thus I do not split the storm-petrels at this time. It seems best to await a worldwide consensus on the families within the Procellariiformes.

7 AOU (1998), Sibley & Ahlquist (1990), and Sibley & Monroe (1990) put the New World vultures with storks. This was based primarily on early DNA evidence but, as Joel Cracraft says in Dickinson (2003), "the evidence supporting the various alternative hypotheses has not been very compelling." Morphological evidence (e.g., Griffiths 1994) supports the traditional placement of the catharids within the Falconidae.

8 Dickinson (2003) reduces Secretarybird to a subfamily of the Accipitridae without any comment. Yet even Sibley & Monroe (1990) continued family status, as did the Birds of Africa handbook (Brown et al. 1982) and, more recently, HBW and Clements. To me this is an "obvious" family — an exceptionally unique and distinctive species that deserves its traditional family rank, as it is not embedded within other lineages.

9 Osprey has been treated as a subfamily of the Accipitridae by many (e.g., Sibley & Monroe 1990, AOU 1998, Dickinson 2003) but I follow HBW in retaining traditional family status. The footnote on the SACC web site says "Although all available data indicate that it is the sister taxon to the hawks and eagles, the rank at which it is treated is rather arbitrary. Given its unique karyotype, which differs from that known for other hawks and eagles, and given that Pandion haliaetus can be recognized as a species in the fossil record as far back as the Miocene, family rank may be more appropriate." To continue to give Pandionidae family status also fits well with my belief that distinctive and unique genera are often best handled as monotypic families.

10 Recent work by Hackett et al. (2008) shows the Gruiformes are an artificial assemblage, and should be restricted to rails, flufftails, finfoots, trumpeters, cranes, and Limpkin. Hackett et al. (2008) suggests that Flufftails are distinct from rails; Clements & IOC now raises them to family level. I concur but more research is needed.

11 The taxonomic status of Magellanic Plover Pluvianellus socialis is uncertain. Sibley & Monroe (1990) and Sibley 1996) considered it a monotypic family on initial DNA hybridization results, but admitted their conclusion was to stimulate further research, rather than a well-supported decision. Strauch (1978) and Chu (1995) used an analysis of morphological characters to argue that it was more closely related to the Chionidae than in its traditional place among the plovers [Charadriidae]. Recent genetic data (Paton et al. 2003) support this relationship. SACC (2006) now considers this a monotypic family. Dickinson (2003) provisionally includes Magellanic Plover within the Chionidae, but both Clements and IOC consider it a full family.

12 IOC now places Egyptian Plover in a monotypic family: "It is a separate lineage that is the outgroup to plovers, ibisbill, stilts and their allies (Hackett et al. 2008). Therefore separated here to its own family tentatively named Pluvianidae." Clements added this family in 2012.

13 It has been contended that Plovers should be split into two Families:

14 Buttonquails are in the Charadriiformes (Hackett et al. 2008).

15 Although I prefer the traditional approach of gulls, terns, and skimmers in separate families, as each group is distinctive in the field, I now follow AOU (1998) and many others in lumping all within the Laridae. Recent evidence suggests terns and skimmers are embedded within the Laridae, e.g., Baker et al. (2007).

16 To quote a footnote in the SACC: "The placement of this order [Opisthocomiformes] is highly controversial. Genetic data have indicated that it is closely related to the Cuculiformes (Sibley & Ahlquist 1990) or Musophagiformes (Hughes & Baker 1999). De Queiroz and Good (1988) found morphological evidence consistent with its placement near Cuculiformes or Musophagiformes.... However, the most recent genetic analysis (Sorenson et al. 2003) failed to find support for a relationship to any of these groups, but found weak support for a relationship to the Columbiformes." Dickinson (2003) also takes the approach used by SACC: Hoatzin is placed just before the Cuculiformes. I now follow them, as does Clements; there is no support for the HBW sequence that places it near Gruiformes.

17 Sibley & Monroe (1990) split the cuckoos into four families — based on DNA divergence — but most other recent checklists continue to place them all (Old World cuckoos, New World cuckoos, anis, and ground-cuckoos) within a single family [Cuculidae]. This is the approach of AOU, SACC, HBW, Dickinson (2003), and Clements.

18 Sibley & Ahlquist (1990) and Sibley & Monroe (1990) split frogmouths into two families: Australian frogmouths [Podargidae] and Asian frogmouths [Batrachostomidae]. Neither HBW nor Dickinson (2003) follow this approach — they consider the two different sets to be subfamilies. However, Holyoak (2001) acknowledges that they differ not only biochemically, but also in nest structure, and could be separate families, and that split is implied in Christidis & Boles (2008). My personal experience suggests that they are two different sets of birds, so while one could go either way, I lean toward the split. The IOC (2009) list does not split them because of the discovery of Rigidipenna inexpectatus, but surely it is more closely related to one of my families, even if we don't know which one yet. For the moment I continue to merge them, following most of the world checklists.

19 Having split the two frogmouths into families, as suggested initially by Sibley & Ahlquist (1990), one must question whether to do the same with the nightjars, as Sibley & Ahlquist (1990) also split the Eared-Nightjars from the rest of the caprimulgids. Christidis & Boles (2008) summarize recent molecular studies that found eared-nightjars to be the sister group to the rest of them, but the IOC (2009) did not consider them of equal rank to other family-level groups. I have waffled on this before, and merge them with Nightjars again.

20 Sibley & Monroe (1990) divided the kingfishers into three families [Alcedinidae, Dacelonidae, and Cerylidae] but most major checklists (HBW, Dickinson 2003) consider these groups to be subfamilies. Christidis & Boles (2008) reviewed the evidence, and adopted the three-way split. Since this change affects Australasia much more heavily than the New World, I followed the approach of Christidis & Boles (2008) for half-a-year. Now I switch back to the mainstream, as the IOC list points out that the while the "three are reciprocally monophyletic groups [they] ... are not the same rank as the other families in the Coraciiformes."

21 This web-based checklist had elevated the Ground-Hornbills to family rank several editions ago, following the persuasive argument by Kemp (1995), and the arrangement of Sibley & Monroe (1990). HBW did not do so, even though Alan Kemp authored the family account for all hornbills (a case where editorial preference trumped the author of the family account). It is thus very encouraging to find that Dickinson (2003) also elevates the Ground-Hornbills to family status, and in 2012, so did Clements. I consider Ground-Hornbills to be the basal lineage, and thus place them before Hornbills in sequence (contra Clements, IOC).

22 Biochemical evidence supports the concept that jacamars and puffbirds are sister groups, but whether they should have their own Order [Galbuliformes] has been controversial. I follow Clements, HBW and SACC in considering them an Order and placing them here before the Piciformes (barbets through woodpeckers). Dickinson (2003) places them within the Picidae and at the end of that Order.

23 The barbets and relatives have been a problem ever since Prum (1988) showed that the traditional classification of Barbets [Capitonidae] and Toucans [Ramphastidae] as separate families was not supported by biochemical evidence. The toucans were more closely related to other New World barbets than the New World barbets were to any of the Old World barbets. Sibley & Monroe (1990) proposed to lump toucans into New World barbets and separate Old World barbets into two different families: Megalaimidae [Asian Barbets] and Lybiidae [African Barbets]. HBW followed the old traditional approach but acknowledged the problem. Dickinson (2003) and AOU (1998) just lumped them all within a single family [Ramphastidae]. This would mean the loss of toucans as a distinctive family, and disguise the significant biodiversity within the group.
      In my view, the SACC has adopted a better approach. It divides these birds into five separate families, explaining: "The families Capitonidae, Semnornithidae, and Ramphastidae are each other's closest relatives with respect to Old World barbets (Burton 1984, Prum 1988, Sibley and Ahlquist 1990, Lanyon & Hall 1994, Barker & Lanyon 2000, Johansson et al. 2001, Johansson & Ericson 2003, Moyle 2004). Old Word barbets are here tangentially treated as separate families, Asian Megalaimidae and African Lybiidae; recent genetic data (Moyle 2004) support the monophyly of the barbet radiations within each region. To emphasize the close relationships among New World taxa, these three families were treated as subfamilies of a single family, Ramphastidae, by AOU (1998). SACC proposal passed to treat these taxa at family rank. Semnornis [Toucan-Barbets] is treated as separate family until affinities resolved. . . Genetic data indicate that Semnornis may be basal to both families (Barker and Lanyon 2000); Moyle (2004) found weak support for that relationship, but also weak support for a sister relationship to Ramphastidae."

24 The most astonishing evidence presented in Hackett et al. (2008) was that falcons [Falconidae] were not closely related to raptors [which now becomes Accipitridae], and might be entitled to Order level. They suggested that its closest relatives were parrots. This innovation requires further confirmation; both IOC and Clements place Falconidae here in sequence.

25 Sibley & Ahlquist (1990) and Sibley & Monroe (1990) raised the Cockatoos to family level distinct from the other Parrots. HBW followed. Dickinson (2003) combined them again into a single Psittacidae noting, in footnotes, that various other groups (e.g., Kakapo Strigops habroptila, the hanging-parrots Loriculus et al.) could also qualify for family status. Christidis & Boles (2008) reviewed the evidence and split the psittaciformes into three families: Cockatoos, Typical Parrots (Psittacidae), and New Zealand Parrots (Strigopidae, which includes Kakapo). I followed that arrangement through the 12th ed. Joseph et al. (2013) suggested a six-way split but Cracraft (2013) reduced this to four families: Strigopidae, Cacatuidae, Psittacidae, and Psittaculidae. That is the approach I follow here.

26 Barker et al. (2004) showed that the New Zealand Wrens were a very early offshoot, basal to all other passerines.

27 Prum (1993) concluded, on the basis of syringeal and osteological characters, that the Asities were embedded within the Broadbill clade and merged them together, but this was challenged on DNA sequence data by Irestedt et al. (2001). That study lacked, however, some broadbill genera. HBW took the more conservative and traditional approach in maintaining the Asities as a family.
      Moyle et al. (2006a) provided the necessary new research to sort this all out. They showed that there were two major clades within the Broadbills — (1) a grouping of the Calyptomenna broadbills of Asia (these are the green broadbills) and the Smithornis broadbills of Africa (these are the lowland forest broadbills in Africa), and (2) a grouping of the remaining Asian broadbills (5 genera) plus Grauer's Broadbill Pseudocalyptomena graueri (a montane species which is an Albertine Rift endemic), plus Asities in Madagascar and the Sapayoa of the New World (see note 29). The Broadbills as a traditional family are only monophyletic if one considers Asities and Sapayoa to be broadbills. The situation is comparable to the barbet/toucan conundrum in which the options are either  to lump all toucans/barbets together or separate them into 5 families, including elevating Toucan-Barbet to family status. The SACC chose the batter option with the barbet/toucan assemblage.
      The DNA evidence in the broadbills best supports (in my view) creating two families of broadbills — the Calyptomenid Broadbills [genera Calyptomena and Smithornis] and the Eurylaimid Broadbills [all other genera, including Pseudocalyptomena] — and retaining the Asities and the Sapayoa as separate families. Finally, AOU, SACC, and Clements have seen the light, and adopted this same common-sense and commendable approach. Clements coined better names: the Calyptomenid Broadbills [genera Calyptomena and Smithornis] become the African & Green Broadbills, and the Eurylaimid Broadbills become the Asian & Grauer's Broadbills.

22 Moyle et al. (2009) showed that the Thamnophilidae are the sister of all other closely related families, and that this sequence best represents their relationships. SACC just adopted this new sequence [antbirds through furnarids] in August 2001, and Clements in the 2012 update.

29 The crescentchests of central & southern South America are not closely related to the tapaculos, where they have been traditionally placed (Irestedt et al. 2002, Chesser 2004b). The South American Checklist Committee has created a new family for this group, the Melanopareiidae.

30 Genetic work (e.g., Irestedt et al. 2002, Chesser 2004b, and others) showed that there were three distinct lineages in the "Formicariidae." The South American and North American checklist committees have handled this by restricting Formicariidae to just two genera of antthrushes [Formicarius, Chamaeza]; created the family Grallariidae for all antpittas except the genus Pittasoma; and assigned the two species of Pittasoma antpitta to the Gnateater family [Rhinocryptidae]. This seems like only a temporary solution to me — the two Pittasoma antpittas are huge compared to the tiny gnateaters; they don't behave like gnateaters; and they may deserve their own family.

31 Genetic data (Irestedt et al. 2002, 2006, Chesser 2004a) indicates that the woodcreepers, traditionally considered a family [Dendrocolapidae] are embedded within the Furnariidae, and within that large group, Geositta and Sclerurus are sister genera that are basal to all Furnariidae (including dendrocolaptids). The SACC (2008) has lumped the woodcreepers with the ovenbirds; I simply follow suit here.

32 The relationships of Sharpbill have been controversial and remain unresolved. It has been included in the Cotingidae, Tyrannidae, or Tityridae. Chesser (2004b) found no strong support for any of these relationships, and Ohlson et al. (2007) found strong evidence against inclusion of Oxyruncus in the Cotingidae. Thus the "traditional ranking of Oxyruncus as a monotypic family was the best portrayal of our understanding of its relationships at that time," said the SACC. Tello et al. (2009) have confirmed the distinctiveness of Oxyruncus relative to the traditional family groupings but found that the tyrannid genera Onychorhynchus, Myiobius, and Terenotriccus grouped with Oxyruncus, and proposed that these genera be moved to Oxyruncidae. No action has yet been taken by SACC on that idea; IOC places it among the Tityridae, although with the three associated 'flycatcher' genera. Given this continuing uncertainty, it seems best to elevate the Oxyruncidae as a Family, so that birders continue to be aware of its uniqueness, but perhaps with the understanding that the Family may, in due course, be expanded to include Royal Flycatcher and various other "flycatchers".

33 The problematic group that includes tityras, becards, mourners and others has been handled many different ways in recent decades (e.g., Ridgely & Tudor 1989). Ericson et al. 2006 proposes the family name Tityridae for the "Schiffornis assemblage," and they also include Sharpbill Oxyruncus cristatus in this new family. Barber & Rice (2007) confirmed the monophyly of the primary elements of this group and also proposed elevation to family rank. The SACC (2008) has accepted this proposal, and so do I. However, there is still uncertainty about Sharpbill and SACC (2008) has provisionally retained it as a family. I merge it with the Tityridae, following Ericson et al. (2006), as that evidence looks persuasive to me at this point.

34 The sequence of the Oscine Passerines (all the rest of the families) is perhaps the most problematic of all issues. As an American, I am most comfortable with the general arrangement of AOU (1998), which has also been generally adopted by SACC, and Clements thus follows suit. These checklists deal only with the New World and do not address the myriad of problems in arranging the Old World families. The proposals of Sibley & Monroe (1990) — wrongly adopted by some field guides — have proved to be partly right but quite wrong in others. The idea of a monolithic Corvidae that arose solely in Australasia is both partly right and partly wrong. Nuclear gene sequencing (Barker et al. 2002) provides some potential directions but is still preliminary. It is, however, now quite apparent that the sequence adopted by HBW (and by me in the 5th edition of this web-based list) was quite out-of-sync with reality.
      In this 9th edition I adopt most of the Oscine Passerine sequence of Gill et al. (2009) except for the final sequence (pipits to Old World sparrows) where I use a sequence similar to AOU/SACC. It seems to me that the IOC sequence is better supported by current literature than Dickinson (2003), which I had used as my primary list in the 8th edition.
      Both the IOC list (Gill et al. 2009) and the Cracraft/Dickinson (2003) list has multiple genera listed as incertae sedis; in other words, a cop-out for now. Alas, I want a complete list even if we have to make our best guesses at this point in time. I have provisionally elevated a few of those genera to family status. Others may warrant similar treatment although, for the most part, it seems likely that most of the 'difficult' genera will eventually go into established families.

35 Sibley & Monroe (1990, Christidis & Boles (1994, 2008), and Dickinson (2003) all lump the Australian Chats with the honeyeaters; so do I. HBW may maintain the Australian Chats as a separate family but the DNA evidence is that that they deeply embedded within the Honeyeaters.

36 Many lists (e.g., Sibley & Monroe 1990, Christidis & Boles 1994) placed the 3 bristlebirds within a broad Pardalotidae that also includes\d the Australasian warblers [Acanthizinae]. Schodde & Mason (1999) explained why the Pardalotidae should be a family, separate from the Acanthizidae (contra Sibley & Monroe 1990); Dickinson (2003) agreed with this separation and further elevated the Bristlebirds [Dasyornithidae] to family status. Christidis & Boles (2008) also adopt this approach.
      Pilotbird Pycnoptilus floccosus, Rockwarbler Origma solitaria, and Fernwren Oreoscopus guttaralis are all now placed within the Acanthizidae [Australasian Warblers]. Dickinson (2003) takes the same approach to the three whitefaces Aphelocephala, as well as the New Zealand endemics Yellowhead Mohoua ochrocephala and Pipipi Finschia novaeseelandiae that are sometimes placed with whistlers.

37 Cracraft & Feinstein (2000) published biochemical and morphological evidence that the three cnemophiline birds-of-paradise (genera Cnemophilus and Lobparadisea) are not closely related to other birds-of-paradise at all, but are quite removed and somewhere near the base of the corvoid phylogenetic tree. This persuaded me to elevate them as a family in my 5th edition on-line family list. Dickinson (2003) now does this in print and places them here, very far removed from the birds-of-paradise. Gill et al. (2009) quite properly now call them all Satinbirds.

38 Elevating the berrypeckers to family status, and then making them into two separate families [Melanocharitidae and Paramythiidae], is a Sibley & Ahlquist (1990), Sibley & Monroe (1990) innovation based on DNA-DNA hybridization studies. The first Passerine volume of HBW states that they plan to follow this approach — so I have the two separate families here. Dickinson (2003) merges all the berrypeckers into one family [Melanocharitidae] but there is no explanation. Data published in Barker et al. (2004) suggests that the two berrypecker groups may not be closely related. Gill et al. (2009) split them into two families, but placed the families next to each other in their sequence.

39 Stitchbird Notiomystis cincta, a New Zealand endemic and an endangered species, has long been considered a Honeyeater. New molecular evidence shows that it is not related to Honeyeaters; the closest relatives are the New Zealand Wattlebirds (the Callaeidae). It has been proposed as a distinct family (Driskell et al. 2007) and I find the evidence compelling. Gill et al. (2009) agreed.

40 Norman et al. (2009) also found that the New Zealand Mohoua [Whitehead, Yellowhead] have no close affinities to any current family. Given what has occurred with Stitchbird (i.e., evidence showed it was an endemic family of New Zealand) and similarly to New Zealand parrot [Strigopidae], it seems that the handwriting is on the wall that the Mohouidae will become a new family in due course.

41 Sibley & Ahlquist (1990) and Sibley & Monroe (1990) had the whipbirds, wedgebills, jewel-babblers, rail-babbler, quail-thrushes, and Blue-capped Ifrit Ifrita kowaldi all within the subfamily Cinclosomatinae in their broad Corvidae assemblage. Dickinson (2003), presumably on unpublished DNA sequencing, split most of these into two families: the five species of quail-thrush Cinclosoma within one family [Cinclosomatidae] with the whipbirds, wedgebills, jewel-babbler and rail-babbler in the other family [Eupetidae]. Jønsson et al. (2007) showed that the Rail-Babbler Eupetes macrocerus was not closely related at all, but was an ancient lineage closer to Rockfowl and Rockjumpers, and it is given family status here.
      Norman et al. (2009) used nuclear DNA to determine the relationships in those groups. They found that Psophodidae should be reserved for just the whipbirds & wedgebills, leaving the jewel-babblers of New Guinea to be placed with quail-thrushes in the Cinclosomatidae. I follow their recommendations. The Ifrit from New Guinea is considered by some authors as incertae sedis and placed (with the two melampittas Melampitta) next to the Birds of Paradise. Norman et al. (2009) showed that Ifrit had no relationship to the Psophodidae, and seems (like the two melampittas) be be most closely related to Monarchidae.

42 Norman et al. (2009), in reviewing the nuclear DNA of many Australo-Papuan aberrant genera, found that three genera, previously considered to be in three different families, showed close relationships with each other and no other groups. These were Crested Bellbird Oreoica gutturalis of arid Australian scrublands, Rufous-naped "Whistler" Aleadryas rufinucha of New Guinea mountains, and Crested "Pitohui" "Pitohui" cristatus of New Guinea hill country. Norman et al. (200) suggested that the relationships of these three were close enough to be united into a single genus (Oreoica) but preferred instead to resurrect Ornorectes for the "Pitohui." While they did not formally designate family–level status for this group, the birds showed no relationship to other families, so I tentatively erect a new family–level taxon here.
      This work, and others, now split the paraphyletic Pitohuis into four genera — and then place them in four families! The "true" Pitohuis (all that is left of genus Pitohui), are closely related to Old World orioles, and I tentatively place them there.
      Norman et al. (2009) also found that the Daphoenositta [Pink-faced "Nuthatch", sometimes placed in Sitellas] of New Guinea, was unrelated to current families. Mottled "Whistler" Rhagologus leucostigma is related to either woodswallows and allies [Artamidae] or African bush-shrikes. These is not yet any good place to put these enigmatic birds.

43 The 'core' lineages appear to be: (a) the core bush-shrikes, (b) the batises and wattle-eyes, and (c) the rest of the malaconotoids; e.g. Fuchs et al. (2004). The helmet-shrikes, vangas, and shrike-flycatchers are all on the same evolutionary branch; Reddy et al. (2012) and proposed that this lineage be designated the Vangidae. In doing so, helmetshrikes become a subfamily [Prionopinae] as to a set comprised of shrike-flycatchers Megabyas & Bias, flycatcher-shrikes Hemipus, wood-shrikes Tephrodornis [Tephrodornithinae]. The two Asian Philentoma are now placed in this expanded Vangidae family.

44 Dickinson (2003), presumably on unpublished DNA sequencing, created this new family, and Christidis & Boles (2008) and Gill et al. (2009) followed. Norman et al. (2009) found that boatbills were a unique lineage, but waffled on where it belonged. It could conceivably belong with an expanded Artamidae.

45 Although Dickinson (2003) separated the woodswallows Artamidae from the butcherbirds & bell-magpies Cracticidae, and implied that Peltops was among the latter, Norman et al. (2009) found that these three lineages formed a single clade; they recommend that Artamidae include all these groups: woodswallows, Peltops, and the butcherbirds & allies. Christidis & Boles (2088) lumped them, but Gill et al. (2009) continues to split them, as does HBW. For the moment I continue to split them into two families, consistent with most world lists. They are quite different types of birds. Mottled "Whistler" Rhagologus leucostigma may belong with the Cracticidae.

46 Moyle et al. (2006b) published genetic evidence that Bornean Bristlehead is an isolated relict from the diversification of shrike-like birds across the Old World tropics. It is in the radiation that includes vangas, bush-shrikes, helmet-shrikes and allies. I follow the placement of Gill et al. (2009).

47 The pachycephaline assemblage of Whistlers, Pitohuis, and allies has been all messed up in prior taxonomies. Jønsson et al. (2008) and Dumbacher et al. (2008) showed that the genus Pitohui was polyphyletic; by the time it was sorted out only half of the Pitohuis remained as even related to pachycephalids, and Norman et al. (2009) suggest that two of these (P. ferrugineus & P. incertus) be assigned to genus Colluricincla; in other words, they are shrike-thrushes. Further, Mottled "Whistler" Rhagologus leucostigma is not a whistler, but rather it is a malaconotoids, while Olive-flanked "Whistler" Hylocitrea bonensis of Sulawesi is related to waxwings! (Spellman et al. 2008).
      The Cracraft/Dickinson (2003) list had its own innovations, elevating the Shrike-Tits [Falcunculidae] and Shrike-Thrushes & Allies [Colluricinclidae] to family level without discussion. I had followed those decisions, tentatively, in the 8th edition list but Norman et al. (2009) appear to suggest that family Pachycephalidae should include all the pachycephalid whistlers & pitohuis (after the non-related species are removed), plus the shrike-tits and the shirke-thrushes & allies. I do so here, although again this is tentative, awaiting further confirmation and consensus.

48 Reddy & Cracraft (2007) found that the Pteruthius shrike-babblers were related to vireo and Erpornis, and unequivocally placed them among the Vireonidae. In further research by Reddy (2008) the evidence suggests that Pteruthius diverged ~29 million years ago and Erpornis diverged ~24 mya (comparable to Donacobius and Olive Warbler, considered by most to be Family-level taxa isolated in the New World, as well as many other family level clades), so I elevate each lineage to Family status. Peter Kovalik kindly advised that lumping the two Old World lineages together, as I initially had intended, would render such a family paraphyletic.

49 The Vireonidae was formerly placed in or next to the nine-primaried oscines in linear sequences (e.g., Ridgely & Tudor 1989). Genetic data (e.g., Barker et al. 2002, 2004) have confirmed Sibley & Ahlquist's (1990) once-controversial finding that the Vireonidae is part of the Corvida lineage.
      On a level equivalent to the finding that Donacobius was an Old World megalurid isolated in the Amazon was the finding that Erpornis zantholeuca (White-bellied 'Yuhina') of Asia is an Old World relict in a clade with New World vireos (Cibois 2003, Alström et al. 2006). Reddy & Cracraft (2007) placed shrike-babblers and Erpornis in Vireonidae, and so have IOC, Clements, etc. But shrike-babblers diverged ~30 mya while Erpornis diverged ~24 mya (Reddy 2008). Given these ancient ages, it is more consistent to place these within their own families.

50 The Magpie-lark and Torrent-lark, formerly considered a separate family Grallinidae [Mudnest-Builders] are embedded within the Monarchs (Baverstock et al. 1992, Christidis & Boles 2008). They no longer warrant even subfamily rank (Dickinson 2003). Other birds thought to be Monarchs, including the Elminia crested-flycatchers of Africa, the African Erythrocercus flycatchers, the Asian genus Philentoma, the Australasian boatbills in genus Machaerirhynchus and others are not. These now appear in other families [e.g., Machaerirhynchidae, Stenostiridae]; Barker et al. (2004), Beresford et al. (2005), Filardi & Moyle (2005). Blue-capped Ifrit Ifrita kowaldi may also be a monarch.

51 Rockfowl and Rockjumpers are early relict offshoots in the passerine assemblage; Cracraft et al. (2004), Jønsson et al. (2007). Each group is exceptional and unique. HBW has given Rockfowl family status. I believe the evidence of early divergence and a long history of isolation and evolution into unique groups, warrants family status for each. The enigmatic Rail-Babbler is most closely related to the Rockfowl and Rockjumpers; Jønsson et al. (2007). Its divergence from them was so long ago that I believe it warrants family status. It is a unique taxon. [Clements (2012 update) finally moved Blue-capped Ifrit Ifrita kowaldi out of the Eupetidae, and to the base of the Pachycephalidae].

52 When HBW began production in the 1990s, there was no intent to list the Kinglets as a family. The evidence that they are a distinct lineage developed, though, and by Vol. 11 the HBW series had a family chapter for them. This location is nearer the base of the passerine tree than traditionally thought; Alström et al. (2006), Jønsson & Fjeldså (2006), Barker et al. (2004), Fregin et al. (2012).

53 The Elminia crested-flycatchers, two Asian canary-flycatchers in the genus Culicicapa, and "fantail in Asia are now formally proposed as family Stenostiridae [Fairy Flycatchers]; Fuchs et al. (2009), see also Beresford et al. (2005). The new family may include other species that have not yet been tested.

54 The enigmatic Hume's Groundpecker Pseudopodoces humilis, traditionally considered a jay, is a terrestrial tit; James et al. (2003), Gill et al. (2005). Many now call it Ground-Tit.

55 Wallcreeper is allied with Nuthatches; e.g., Jønsson & Fjeldså (2006). Whether to lump them with Nuthatches or maintain their traditional family status is a matter of opinion, not science. I prefer the traditional family rank; HBW and Gill et al. (2009) maintained it as well.

56 Beresford et al. (2005) showed that the Nictators were a separate lineage that diverged long ago. This enigmatic group has been variously placed in bulbuls or babblers. Fregin et al. (2012) placed it here in the sequence.

57 Initial genetic evidence suggests that Bearded Reedling Panurus biarmicus was not closely related to the parrotbills with which it has been traditionally placed; Alström et al. (2006), Jønsson & Fjeldså (2006), Barker et al. (2004), Cibois (2003). Fregin et al. (2012) place it here in sequence.

58 The Macrosphenidae is a lineage that includes crombecs and certain African warblers, a group described by Beresford et al. (2005), and only recently (2011) acknowledged by Clements and others.

59 The break-up of the Old World Warblers is discussed in a separate three-page web set; Alström et al. (2006) formally proposed a number of the new family names used here. "Megaluridae" was initially proposed for the Grassbirds, but Locustellidae has priority.

60 The genus Donacobius ("Black-capped Mockingthrush") of South America is an ancient offshoot of the locustellid warbler group (Barker 2004, Alström et al. 2006). Some prefer to include Donacobius within the Grassbirds to emphasize its closest relatives, but it has evolved in isolation for so long that I think it should be considered it own family [Donacobidae], consistent with the treatment of other similar situations.

61 Cibois et al. (1999, 2001) showed that there was a distinct radiation of warbler-like birds in Madagascar eons ago. For the moment, I call them the Bernieridae [Malagasy Warblers], and this has since been adopted by Clements and IOC.

62 A surprise in the DNA analysis of babblers was that genus Pnoepyga, which includes 4 species of tiny, short-tailed, terrestrial "wren-babblers," were not within the babbler evolutionary radiation; Gelang et al (2009). They did not know exactly where to place this "long-branch" lineage, but it is clearly not within the other babbler families. Gelang et al. (2009) proposed the family name Pnoepygidae. They did not propose an English name of the birds within this new family. Pnoepyga is just one of a half-dozen genera that have been called Wren-Babblers (e.g., Rimator, Ptiolcichla, Kenopia, Napothera, Spelaeornis), so the new family must be called something other than just "wren-babblers." The 2011 update of Clements checklist calls them "cupwings," and I follow.

63 This surprising location for the swallows was revealed using 7 nuclear markers in Reddy et al. (2012).

64 Some of the "Old World Warblers" [the previous Sylviidae] are actually babblers, including the Sylvia 'warblers'. This had implication for the proper use of the "Sylviidae" name, but that was sorted out satisfactorily. The babblers themselves are an eclectic group of birds that can be handled taxonomically in various ways. Gelang et al. (2009) proposed setting up five babbler subfamilies, but various world checklists (e.g., Clements, IOC) and I initially chose to raise them to Family level. More recently, a better reasoned and more nuanced position was proposed by Moyle et al. (2012): the three core babbler clades are best considered subfamilies, but White-eyes & allies are better considered a family, as are Sylvids. I now follow that proposal with one addition. I split the main two sylvid clades into two Families, re-erecting the Paradoxornithidae for parrotbills & allies.

65 Fregin et al. (2012) found molecular evidence that the enigmatic African species Green Hylia Hylia prasina was near the long-tailed tits, just had been suggested by Beresford et al. (2005). Sefc et al. (2003) had found a sister relationship between Hylia and Tit-hylia Pholidornis rushiae, based on mt DNA. Fregin et al. (2012) considered the elevation of these two species in family Hyliidae to be "reasonable," but awaited nuclear DNA evidence on Pholidornis before making that proposal. As it does seem likely the Hyliidae will be proposed in the future, I elevate that Family provisionally now.

66 Fregin et al. (2012) used nuclear DNA evidence to better locate the taxonomic position of the Cettiidae here, but they also proposed two offshoot Families: the Scotocercidae for Scrub Warbler Scotocerca inquieta of north Africa and the Middle East, and the Erythrocercidae for the three species of "warbler-like flycatchers" in the African genus Erythrocercus. Scrub Warbler fits well within the morphologically diverse Cettiidae and has not previously been proposed as anything like a Family-level taxon. Fregin et al. (2012) propose family status primarily because "it is separated from [the core] Cettiidae . . . by a long internode." If the evidence of a "long internode" were to be adopted as a marker for Family level status, there are a host of similar examples in the Passerines, including within the families Macrosphenidae and Sylviidae in their own study, to which they do not apply the same standard. My feeling is that the "Scotocercidae" is overreaching and not consistent with modern views of Family level status. However, the three species of Erythrocercus "flycatchers" are morphologically and ecologically distinctive, and separated more distantly separated from the Cettiidae plus Scotocerca. The Erythrocercidae proposed by Fregin et al. (2012) might marginally be on the cusp of Family status (evidence about the age of the lineage would be useful; the vast majority of passerine families are 20 mya plus in age of divergence), and so I very tentatively accept it for the moment.

67 Gill et al. (2009) and Clements (2011) include Spot-throat Modulatrix stictigula, Dapplethroat Arcanator orostruthus, and Gray-chested Babbler Kakamega poliothorax in this family, as well as the two Promerops sugarbirds. Whether that holds is something to watch in the future.

68 Fuchs et al. (2006a) showed that the Hyliotas were an early radiation at the base of the passerine tree. I give family rank to each of these early lineages, pending more thorough analysis. Whether this status will survive will depend upon future studies. Gill et al. (2009) gave it family status and placed it here.

69 The Muscicapidae includes not only the traditional Old World Flycatchers, but numerous Old World chats and redstarts that used to be placed with Thrushes. It is now a huge assemblages containing all these birds; Sibley & Ahlquist (1990), Dickinson (2003), Jønsson & Fjeldså (2006). It does not, however, include the canary-flycatchers in the genus Culicicapa, and a few other genera, that belong to the family Stenostiridae or other families; e.g., Barker et al. (2004).

70 The exact relationships of the Philippine endemic genus Rhabdornis was not known until Lovette & Rubenstein (2007). They found them to be the earliest offshoot of the Asian-Pacific clade of starlings, but after the split of African starlings, thus making Rhabdornises embedded within the Sturnidae. Zuccon et al. (2006) had foreshadowed this possibility, which has since been followed by the IOC list (Gill & Donsker 2010) and Clements.

71 The Oxpeckers have long been considered aberrant Starlings, but they diverged quite some time ago and are only rather distantly related; Cibois & Cracraft (2004). Fry & Keith (2000) gave them family rank, and I followed them several editions ago in this on-line list. This still seems to be the preferred treatment; e.g., Zuccon et al. (2006), Lovette & Rubenstein (2007).

72 The Chinese endemic Przevalski's 'Finch'/Pink-tailed 'Bunting' Urocynchramus pylzowi is not closely related to buntings or finches; Groth (2001). It is placed in a separate clade by Jønsson & Fjeldså (2006). I gave it preliminary family status, and so did both Clements and Gill et al. (2009).

73 The A.O.U. (1998) considers Olive Warbler a family. It is an Old World relict, most closely allied to Accentors, that is isolated in the New World; Jønsson & Fjeldså (2006).

74 A real surprise discovered while genetic sequencing of "wren-babblers" was that Spotted “Wren-Babbler" Elachura formosa of the eastern Himalayas was an early offshoot of the lineage leading to the Bombyciloidea (waxwings and allies). Alström et al. (2014) proposed Family rank for this lineage, the monotypic Elachuridae. For the moment I place it here, before the rest of the Bombyciloidea.

75 Another big surprise was the finding that Olive-flanked "Whistler" Hylocitrea bonensis of montane Sulawesi was not a pachycephalid but rather most closely related to the bombycillids (e.g., Spellman et al. 2008). As stated above, I prefer to give family rank to each of the bombycillid clades (waxwings, silky-flycatchers, Palmchat, Hypocolius, and now this one). Thankfully, so does Gill et al. (2009) and Clements.

76 Hypocolius is traditionally given family rank. Genetic evidence confirms that its closest affinities are with waxwings and relatives (e.g., Spellman et al. 2008). It is equally appropriate to put all these groups into one family, with multiple subfamilies, or to maintain separate family rank for each group. I prefer the latter course, and HBW does as well. Gill et al. (2009) and Clements (2011) retain all the bombycillid families also. I think that is a much better choice.

77 The A.O.U. (2010) now accepts the Calcariidae as a family, following Jønsson & Fjeldså (2006).

78 The parameters of the Thraupidae [Tanagers] is now much better known; Barker et al. (2013), Burns et al. (2014). The Galapagos finches and Bananaquit belong here. Barker et al. proposed a number of new families in this assemblage. I have provisionally accepted the Rhodinocichlidae, Mitrospingidae and Phaenicophilidae. Zeledonia [wren-thrush], Teretistris [two Cuban warblers], and Icteria [Yellow-breasted Chat] remain unresolved, and for now remain with the Parulidae.

79 The Emberizidae must be split into two families or the nine-primaried passerines become paraphyletic; Barker et al. (2013). The proposed that the New World Sparrows be split as the Passerellidae.

80 The exact parameters of the Cardinalidae [Cardinals, Grosbeaks & allies] are not yet known, but it seems that the 'traditional' set of species assigned to this family is non-monophyletic. Genetic data published by Klicka et al. (2007) showed that a monophyletic Cardinalidae would require removal of Saltator and Parkerthraustes and inclusion of Amaurospiza, Granatellus, Piranga, Habia, and Chlorothraupis. This means moving various 'warblers' and 'tanagers' to this group, including the North American 'tanagers' in Piranga [e.g., Summer, Hepatic, Scarlet & Western Tanagers] and moving the Saltators and others to Thraupidae.

81 The traditional Tanager genera Euphonia and Chlorophonia have been moved from the Thraupidae to the Fringillidae and the SACC and AOU now list them as a subfamily of Finches. This was based on the genetic data work of Klicka et al. (2000, 2005), Yuri & Mindell (2002), and others. It is consistent with aspects of the biology of the euphonias and chlorophonias with respect to voice, diet, and nesting biology.

82 Fjeldså et al. (2010) showed that this Mindanao, Philippines, endemic Hypocryptadius cinnamomeus [Cinnamon Ibon], formerly considered a "white-eye," was actually a relict forest canopy sparrow that diverged from the rest of the Passeridae ~31 mya. Fjeldså et al. (2010) suggested only subfamily status. Consistent with the way other similar taxa are treated, I tentatively place it at Family level.

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