Proposal (61) to South American Classification Committee


Change English name of Pterodroma defilippiana to De Filippi's Petrel


Current SACC status: Currently, Pterodroma defilippiana appears on the SACC list as Masatierra Petrel. These footnotes are associated with the taxon:


8. Pterodroma defilippiana has been considered a subspecies of P. cookie (REF).

9. Called "Mas a Tierra Petrel" in Murphy (1936) and Carboneras (1992b). Called "Defilippe's Petrel" in Sibley & Monroe (1990) and "Defilippi's Petrel" in Stattersfield (REF). Also Howell et al. (1996) noted that the species is named for F. de Filippi, so the name should be "de Filippi's Petrel". The latter, however, is difficult to spell correctly, and certainly confuses Chileans who know the Philippi's as the ornithologists that had a large influence in Chile.

10. Pterodroma cookiiP. defilippiana, and P. longirostris are members of the "Cookilaria" species group, also including extralimital P. hypoleucaP. nigripennisP. axillaris, and P. leucoptera; they are considered to be each others' closest relatives (Jouanin and Mougin 1979).



Historically, there have been two competing names for this small 'Cookilaria' petrel, both of which have spelling variants:


a) Mas Atierra Petrel (Murphy 1929); Mas a Tierra Petrel (Murphy 1936, Carboneras 1992); Masatierra Petrel (SACC)


b) Defilippe's Petrel (Sibley & Monroe 1990, Roberson & Bailey 1991, Collar et al. 1995); Defilippi's Petrel (Stattersfield per SACC; several tour groups use this name in Internet listings); de Filippi's Petrel (Howell et al. 1996, Birdlife International 2000).


The AOU (1989) added to the confusion by using the name "Juan Fernandez Petrel," long established as the English name of P. externa, but that error was quickly withdrawn (AOU 1990) and can now be ignored.


Summary of argument for proposal:

This is a case of a taxon with two competing English names, one a name for a breeding island (Masatierra Petrel) and one a patronym (De Filippi's Petrel). Both competing names are associated with confusion. Masatierra Petrel is confusing because of the interplay of the species' taxonomic history with a now-discredited "Masafuera Petrel" (now known by the English name of Stejneger's Petrel); Masatierra and Masafuera are names of two islands in the Juan Fernandez group and easily confused with each other. De Filippi's Petrel might be confused by Chileans with the Philippianas, unrelated early ornithologists. Both competing names have confusing spelling variants.


De Filippi's Petrel is a better name because (a) we are choosing an English language name and the Masatierra/Masafuera confusion is grounded in foreign language problems; (b) the species' breeding range is well beyond Masatierra Island and, in fact, in may no longer nest there; and (c) all closely related species are known by patronyms. It provides better symmetry for this taxon to bear a patronym also.


Detailed argument in favor of proposal:


My interest: I am the senior author of a paper (Roberson & Bailey 1991) that unraveled some of the distribution and identification mysteries of the small Pterodroma petrels. The paper was based both of extensive field work at sea in the eastern tropical Pacific and off California, and thorough museum study, primarily at USNM and AMNH (Roberson; supported by a Chapman Fund grant) but also in New Zealand (Bailey). This paper was the first to clarify the distribution of P. defilippiana (subtropical southeastern Pacific; no records for the northern hemisphere) and the first to propose field identification criteria. Prior to our paper, this species was considered essentially "identical" to Cook's Petrel P. cookii (e.g., Tyler & Burton 1986, Dunn 1988). We showed it could be readily identified on a number of features, including diagnostic tail pattern. Since our paper, the at-sea identification of this bird has been further clarified (Spear et al. 1992, Howell et al. 1996).


Taxonomic history: This taxon was named for professor F. de Filippi (Giglioli & Salvadori 1869). Numerous other 'species' in the group were described through the late 1800s, from widespread points in the Pacific Ocean, until Matthews (1912) lumped them all into a single species P. cookii. Murphy (1929) reviewed the entire situation and concluded there were actually two species: pale-headed P. cookii (including cookii, nigripennis, axillaris) and dark-crowned P. leucoptera (including leucopteralongirostris, and hypoleuca). He called the dark-headed birds nesting in the Juan Fernandez Islands the "Mas Afuera Petrel" (P. l. masafuera) and used the name "Mas Atierra" for the pale-headed birds nesting there (P. c. defilippiana). He also described a new race -- P. c. orientalis -- for birds collected off Chile but looked very much like nominate P. cookii of New Zealand. Thereafter, Falla (1933) described Pycroft's Petrel P. pycrofti and opined that Murphy's "orientalis" could actually be immature Cook's Petrels on migration. It is now well-established that P. cookii winters in the eastern Pacific and "orientalis" has been suppressed (e.g., Imber 1985).


But the confusion spawned by Murphy (1929) has cast a long shadow. He was initially unable to place the taxon longirostris, described from a bird taken at sea off Japan by Stejneger (1893), not having seen the type specimen, but thought it likely belong to his leucoptera group. Soon thereafter he referred five other specimens from the northeastern Pacific to longirostris in his "leucoptera" group (Murphy 1930). Moffitt (1938) followed Murphy's taxonomy by referring to birds taken off California (Loomis 1918) as P. leucoptera masafuera. It wasn't until Falla (1942) that the birds off Japan were shown to be migrant longirostris from the Juan Fernandez, with longirostris taking priority over Murphy's "masafuera." Yet the original label that the offshore California specimens were "leucoptera" lingered for years. Even though they were actually Stejneger's Petrel P. longirostris, some literature referred to them as White-winged Petrel P. leucoptera (e.g., Pough 1957).


The subgenus Cookilaria has likewise undergone radical expansions and restrictions. Jouanin & Mougin (1979) lumped pycrofti with longirostris, defilippiana with cookii, and brevipes with leucoptera, and considered them to form a superspecies. They placed axillaris and nigripennis as another superspecies, but considered hypoleuca to be "distinct."


The popular literature has hopelessly confused an already complex situation. The widely influential Harrison (1983) confused defilippiana with Murphy's discredited 'orientalis', and failed to include it in his original guide. After I had personally pointed this problem out to him (in litt.), he remedied it somewhat by including defilippiana in his next book (Harrison 1985) but continued the confusion by showing its range to include old "orientalis" (=cookii) specimens north of the Equator and stated that defilippiana ranged to 12 degrees North. This was in error; all specimens north of the Equator (indeed, all specimens of any of cookii/defilippiana group north of 12 degrees South) are actually of Cook's Petrel P. cookii. Finally, after yet another letter from me, a revised edition (Harrison 1987) restricted the range of P. defilippiana somewhat (but still too far north) but he painted an incorrect tail pattern and misidentified published photos (we corrected these identifications in Roberson & Bailey 1991).


Evaluating name choice:


In evaluating which of two competing English names should be used for P. defilippiana, it must be recognized that the literature, both scientific and popular, is filled with confusion stemming from Murphy's "Mas Afuera Petrel "P. leucoptera masafuera" (now known to be Stejneger's Petrel P. longirostris) and his "orientalis" race of P. cookii that has been confused with P. defilippiana.


We are evaluating the choice of an English name. To English speakers, "Mas Afuera" is a foreign word easily confused with "Mas Atierra" (sometimes spelled "Mas a Tierra" or, as you currently have it, "Masatierra"). I consider that confusion to be as great to English speakers as the alleged confusion associated with Chileans (in your current footnote 9) in distinguishing between the Philippianas and Professor de Filippiana. Even if it were just a choice between those two sets of confusion, I would prefer the patronym because we are choosing an English name, not a Chilean name.


But the evaluation does not end there. P. defilippiana nests on the Juan Fernandez Islands of Santa Clara and Robinson Crusoe; it is only the latter island that is known locally as Mas a Tierra Island. But P. defilippiana also nests on the Islas Desventuradas of the San Ambrosio and San Felix group, some 400 miles farther north. In this thus not restricted to "Masatierra" Island (if spelt that way) and such a label is misleading. Furthermore, recent studies (e.g., de L. Brooke 1987) suggest that the taxon is now extirpated from Robinson Crusoe = Masatierra Island, and, within the Juan Fernandez, is now restricted to Santa Clara Island. Referring to the bird by the name of an island on which it no longer exists elicits additional confusion.


But that is not all. All recent reviewers (e.g., Jouanin & Mougin 1979) consider P. defilippiana to be closely related to three other small petrels within the Cookilaria group:


P. cookii Cook's Petrel

P. pycrofti Pycroft's Petrel

P. longirostris Stejneger's Petrel


Given that all of these have patronyms for their English names, it is both logical and attractive that the fourth member of the group also bears a patronym, to wit,


P. defilippiana De Filippi's Petrel


A word about spelling:


It has already been noted that each of the competing name has been spelled three different ways in the literature. It is not as if we have one non-confusing name and one confusing name; they are both subject to confusion. P. defilippiana was named after professor de Filippi but his name has been Latinized in creating the species names, and has usually been Anglicized in creating the patronym. As between the competing spellings of "Defilippe's" and "Defilippi's," we (Roberson & Bailey 1991) proposed that the former be "conserved" to avoid further confusion, but since our publication, the term "de Filippi's" (Howell et al. 1986) and "Defilippi's" have been used. I now consider "Defilippe's" to be the inaccurate and withdraw any suggestion that it should be conserved.


This leaves spelling choices: de Filippi's versus Defilippi's versus De Filippi's Petrel. Consistent with the AOU practice in similar cases (e.g., Le Conte's Sparrow), it seems best to retain as much of the foreign spelling structure as possible. Thus a space between the "de" and the "Filippi's" seems best. We are left with the question of de Filippi's versus De Filippi's (with a capital "D").


Unfortunately, the Le Conte's Sparrow example is not that helpful on this final question. John J. Audubon named the sparrow for his friend Dr. Le Conte who, though of French background, was born in the U.S. and used the spelling with a capital "L" (Terres 1991). However, I believe it is standard protocol that in lists of English language names of bird species, it has been AOU policy that the specific name begins with a capital letter (stemming, of course, from the general proposition that Yellow Warbler is preferred over the term "yellow warbler" widely used by the non-technical literature). Further, capitalizing the "D" would reduce any confusion by Chileans to the Philippians.


For all these reasons, I propose that P. defilippiana be known by the English name of De Filippi's Petrel.


Literature Cited

American Ornithologists' Union. 1989. Thirty-seventh supplement to the A.O.U. Check-list of North American birds. Auk 106:532-538.

American Ornithologists' Union. 1990. Errata to the thirty-seventh supplement to the A.O.U. Check-list of North American birds. Auk 107:274.

Birdlife International. 2000. Threatened Birds of the World. Barcelona & Cambridge, U.K., Lynx Edicions & Birdlife International.

Carboneras, C. 1992. Family Procellariidae (Petrels and Shearwaters) in Handbook of the Birds of the World (J. del Hoyo, A. Elliott, & J. Sargatal, eds.). Vol. 1. Lynx Edicions, Barcelona, Spain.
Collar, N. J., M.J. Crosbey, and A. J. Stattersfield, ed. 1995. Birds to Watch 2: The World List of Threatened Birds (Birdlife Conservation, No 4). Birdlife International, Cambridge, U.K.

de L. Brooke, M. 1987. The birds of the Juan Fernandez Island, Chile. ICBP study rept. 16, Cambridge, U.K.

Dunn, J. L. 1988. Tenth report of the California Bird Records Committee. W. Birds 19:129-163.
Falla, R. A. 1933. Notes on New Zealand petrels. Rec. Auck. Inst. Mus., vol. 1:173-180.

Falla, R. A. 1942. Review of the smaller Pacific forms of Pterodroma Cookilaria. Emu 42:111-118.

Giglioli, H. H., and T. Salvadori. 1869. On some new Procellariidae collected during a Voyage round the World in 1865-68 by H.I.M.'s Magenta. Ibis, New Series, 5:61-68.

Harrison, P. 1983. Seabirds: an Identification Guide. Houghton Mifflin, Boston.

Harrison, P. 1985. Seabirds: an Identification Guide, rev. 2nd printing. Houghton Mifflin, Boston.

Harrison, P. 1987. Seabirds of the World: a Photographic Guide. Christopher Helm, Bromley, U.K.

Howell, S. N. G., S. Webb, and L. B. Spear. 1996. Identification at sea of Cook's, de Filippi's, and Pycroft's petrels. West. Birds 27:57-64.

Imber, M. J. 1985. Origins, phylogeny and taxonomy of the gadfly petrels Pterodroma spp. Ibis 127:197-229.

Jouanin, C. and J. L. Mougin. 1979. Order Procellariiformes, in Check-list of Birds of the World. E. Mayr and G. W. Cottrell, eds. Vol. 1, 2d ed:48-121. Mus. Comp. Zool., Cambridge, MA.

Loomis, L. M. 1918. A review of albatrosses, petrels, and diving petrels. Proc. Calif. Acad. Sci. 2, pt. 2, no. 12:1-187.

Matthews, G. M. 1912. The Birds of Australia. Vol. 2. Witherby & Co., London.

Moffitt, J. 1938. Two southern petrels in the north Pacific. Auk 55:255-259.
Murphy, R. C. 1929. On Pterodroma cookii and its allies. Amer. Mus. Novitates 370.

Murphy, R. C. 1930. Birds collected during the Whitney South Sea expedition. Amer. Mus. Novitates 419.

Murphy, R. C. 1936. Oceanic Birds of South America. Vol. 2. Amer. Mus. Nat. Hist., New York.

Pough, R. H. 1957. Audubon Western Bird Guide. Doubleday, Garden City, N.Y.

Roberson, D., and S. F. Bailey. 1991. Cookilaria petrels in the eastern Pacific Ocean: Identification and distribution. Part I: Am. Birds 45:399-403. Part II: Am. Birds 45:1067-1081.

Sibley, C. G., and B. L. Monroe, Jr. 1990. Distribution and Taxonomy of Birds of the World. Yale Univ. Press, New Haven, CT.

Spear, L. G., S. N. G. Howell, and D. G. Ainley. 1992. Notes on the at-sea identification of some Pacific gadfly petrels (genus Pterodroma). Colonial Waterbirds 15:202-218.

Stejneger, L. 1893. Notes on a third installment of Japanese birds in the Science College Museum, Tokyo, Japan, with descriptions of new species. Proc. U.S. Nat. Mus. 16:618-620.

Terres, J.K. 1991. The Audubon Society Encyclopedia of North American Birds. Random House, New York.

Tyler, W. B., and K. Burton. 1986. A Cook's Petrel specimen from California. West. Birds 17:79-84.


Don Roberson, October 2003


Addendum from Roberson, 10/22: "one thing I failed to mention in the De Filippi's vs. Masatierra name issue is that ALL research on the taxon published within the last 30 years (or at least all of which I am aware) has used some variant on De Filippi's as the name. The only recent usage of Masatierra or variants has been European publications (e.g., first vol. HBW and the Howard-Moore checklist), which seem unaware of recent research on P. defilippiana. For just one more example, see the current detailed compilation of Pacific seabirds at


At this point, I think De Filippi's (or variants) is "widely accepted" within the seabird community and no one within that research community uses the older and essentially discarded alternative, as far as I know. I think it is only on your SACC list because you chose Howard-Moore as a baseline; their impact on petrel names seems almost accidental. They are clearly out-of-touch with the seabird community by using "Gould's Petrel" for Pterodroma leucoptera (the seabird world very broadly uses White-winged Petrel, reserving "Gould's Petrel" for the nominate race if one splits up this taxa) but that's a different issue, although not unrelated.....




Comments from Stotz: "NO. It is at times like this that I want to abdicate our responsibility for English names. Like I really care what a handful of people refer to an obscure gadfly petrel as. But of course I am going to go on for a page about this. Like Van, I am inclined to stick with older established names, so Masatierra gets precedent unless a compelling reason can be shown for changing to something else. I am afraid that I don't see any compelling reason for change. The arguments against Masatierra seem to be; 1) confusion with Masafuera 2) not limited to Masatierra, and perhaps extinct there; 3) not really an English name. My responses are 1) Masafuera is not currently being used, and if birders can avoid confusing White-bellied, White-bibbed, White-breasted, and White-throated Antbirds (among a million examples), they can handle Masatierra and Masafuera. 2) People who can talk about Connecticut, Tennessee and Nashville Warblers have no real right to complain about the fact that a bird is not restricted geographically as much as the name might imply. A couple of South American examples include Peruvian Diving-Petrel and Mato Grosso Antbird. Pterodroma examples include Bonin, Trindade, Phoenix and Kermadec Petrels, all of which breed on more than the island used in their name. 3) This is a place name and we have dozens of place names from other languages that we use as modifiers for bird names. Again Petrels have some of the least familiar of these names including Trindade and Juan Fernandez. It is not clear to me why a place name is less "English" than the name of some random Italian.


If we change to De Filippi's, I think Don is right that it should be De Filippi's rather than the other possible orthographic variants. In terms of the first letter being upper case. D'Orbigny's Chat-Tyrant and D'Arnaud's Barbet, both named for people whose names were written with lower case d, are written with capital D in everything I've looked at. My only question is whether De Filippi is better than Filippi. I don't know exactly how Italian's treat "de." In Brazil at least somebody who is "de something" is usually treated as just something. Jose Maria is an example, he is almost invariably alphabetized as Silva, not de Silva (although occasionally Cardoso de Silva). Of course, Meyer de Schauensee is either the three names or de Schauensee. So I don't know. Maybe somebody does?"


Comments from Robbins: "[YES] I find Roberson's rationale for the change to be compelling. Clearly, he has spent a fair amount of time thinking about this and I find the name "Masatierra" to be confusing and uninformative. As shown by my past voting, I have no qualms about changing names just because of "history". Hence, I vote yes for the change.


Comments from Jaramillo: "NO -- leave as Masatierra Petrel. Gosh, I didn't think that there would be that much interest in this topic, but I guess there is. Seabird enthusiasts, along with gull enthusiasts, are about as avid as you can get! The more opinions the merrier as far as I am concerned. Well let's start with what everyone knows by now, but which has to be well understood. Both competing names here are confusing, neither one is a shoo-in. On the other hand, the De Filippi name and its varying spellings has had a wider circulation in recent years and part of the confusion on how to properly spell it is due to plain old confusion as to how the Italian man (de Filippi) spelt his name, and plain old not knowing how to spell the proper name (my problem). Having led tours in Chile and having had to deal with Pterodroma defilippiana now for years with birders it is obvious that this name is confusing and causes spelling problems for most of us. I don't know why, but I keep misspelling it, perhaps due to the trauma of watching the name unfold in so many various ways. Roberson and Bailey (1991 -- see references in proposal) spelt it Defilippe's as he notes, but they now think this was an error. So Roberson himself has found the name to be problematic, as I have. Even in the new proposal there is a need to concentrate on whether de Filippi's or De Filippi's is more appropriate, rightfully choosing the latter in this case. I think that leaving out the confusion that Chileans, or others who know the work of the Philippi's in Chile, may face with this name it is still one riddled with problems. Also I will mention that all things being equal I would prefer a name that tells you something about the bird as opposed to a patronym. The name Masatierra Petrel has had little use in the recent past, and I would argue that the different spellings of this name have not caused nearly as much confusion as with De Fillippi's. So, in summary. I would rather do away with the De Filippi's problem by changing the name of this petrel, and hopefully begin a less confusing future for the English name of this creature. I don't think that Masatierra Petrel is confusing, even for English speakers and it sure has a more pleasant sound to it. Also I should mention that we do have another species Masafuera Rayadito that uses the name of the outer island in the Juan Fernandez group and as such using Masatierra seems equally ok to me. Furthermore the argument that this petrel does not breed on Robinson Crusoe Island (Masatierra) is not proven, researchers I spoke to at the NOC seemed to think that it does. The other local breeding island (Santa Clara) is actually a satellite of Masatierra about a mile offshore from that island. In a sense Santa Clara Island can be considered to be part of Masatierra when considering that the third island (Masafuera) is 170 km from either of the former two islands. I think that what one like's will be just a matter of personal taste here, both names have their problems. Yet choosing Masatierra does the following: removes a patronym, removes a series of confusing spellings and names that have had people arguing for a few years now, adds a bit of geographically information to the name, and it just plain sounds catchier to me."


Comments from Zimmer: "I vote "NO" for reasons outlined by both Doug and Alvaro. I really do find the proposed name more confusing (particularly the spelling), and less easy on the tongue, and I don't see any compelling reason to change. I also think the geographic name is more informative."


Comments from Stiles: "[NO.] De Fillipi's Petrel: this is one I have no strong feelings about.. if nothing else, I would advocate Mas a Tierra (without accent? In Spanish it would be Más) instead of Masatierra. Spelled correctly, it's not really so misleading, and LOTS of Neotropical birds no longer occur at their type localities!! In general, I favor using toponyms for highly localized species as this calls attention to such distributions and to their actual or potential vulnerability."


Comments from Nores: " YES. Los fundamentos dados por Roberson parecen válidos. Si el que describió la especie fue de Filippi lo lógico que sea De Filippi´s Petrel o Defilippi´s Petrel, pero no Defilippe´s Petrel."


Comments from Schulenberg: "YES. What a lot of wailing and gnashing of teeth over esoteric issues. Most of us don't give a rat's ass about Pterodroma and what to call them. Given a choice between two problematic names, one of which in fact has a rabid fan base (current seabird biologists/enthusiasts), why *not* follow the currently more widespread name (De Filippi's Petrel)? Sheesh."