Proposal (995) to South
American Classification Committee
(Note from Remsen: This proposal was submitted to the North American
Classification Committee and passed, and it is submitted here with permission
from Eric VanderWerf. Note that brewsteri,
as represented by the subspecies etesiaca, breeds in the SACC area on
Isla Gorgona, Colombia.)
Treat Sula brewsteri as a
separate species from Brown Booby S.
leucogaster (Part A), and if Part
A passes, establish English name for Sula
brewsteri (Part B)
Part A.
Background:
Note: much
of the background information below is from VanderWerf et al. (2023)
The Brown Booby (Sula leucogaster) is a pantropical seabird found in the Pacific,
Atlantic, and Indian Oceans that exhibits geographic morphological variation.
Five subspecies have been described based on differences in color of the
plumage, bill, and facial skin (Table 1; Nelson 1978, VanderWerf 2018a,
Schreiber & Norton 2020). Sula l.
plotus has the largest geographic range, from the Red Sea and Indian Ocean
east to the central Pacific. In both sexes of S. l. plotus, the head is
dark brown, and the bill is yellow (females) or bluish-yellow (males). The
nominate subspecies, S. l. leucogaster,
occurs in the Atlantic and Caribbean and is similar to plotus but has a more pinkish bill. The form of Brown Booby
occurring in the eastern Pacific, S. l.
brewsteri, is the most distinctive morphologically and originally was
described as a separate species called Brewster’s Booby (S. brewsteri; Goss 1888). Male S.
l. brewsteri have a geographically variable white head, a more grayish-blue
bill, and a more greenish-blue gular pouch. In the Gulf of California and the
western coast of Mexico south to the Revillagigedo Islands, male S. l. brewsteri have a white head and a
pale brown upper neck. On some islands off Central America and South America,
the white on the head of males is restricted to the forehead, and this form
sometimes is considered a separate subspecies, S. l. etesiaca, but also has been grouped with S. l. brewsteri (Harrison 1983, Schreiber & Norton 2020). The
form breeding on Clipperton Island is the palest, with the entire head and neck
white in males, and is sometimes referred to as S. l. nesiotes (Heller and Snodgrass 1901, Pitman & Balance
2002, Schreiber & Norton 2020).
As noted above, Brewster’s Booby originally was
described as a species, S. brewsteri,
by Goss (1888) based on type specimens from San Pedro Mártir Island, Mexico. In
the description, Goss noted that characteristics of the species included the
pale color of the head and neck, especially in the male, a dark brown iris with
a narrow outer ring of grayish-white, and “unfeathered parts also differently
colored.” In 1944, S. l. brewsteri was lumped with other forms of
the Brown Booby (Wetmore et al. 1944), who cited “Peters, checklist, 1, 1931”
and Wetmore (1939) as justification for the lump. Wetmore (1939) stated that
“while apparently uniform over large areas of the tropical oceans of the world
there are three (barely possibly four) races of Sula leucogaster to be recognized…on the Pacific coast of the
Americas… These differ from all other subspecies of the species.” Wetmore
(1939) discusses at length the variation among the forms in the eastern
Pacific, which seems to support their distinction, and did not offer any
explanation for why S. l. brewsteri
should be lumped with other forms of the Brown Booby, yet he did so, and this,
paradoxically, served as the basis for the lumping by Wetmore et al (1944).
Genetic population structure of Brown Boobies
largely matches patterns of morphological variation (Steeves et al. 2003,
Morris-Pocock et al. 2010, 2011). Mitochondrial haplotypes were not shared
between the eastern and central Pacific or between the eastern Pacific and
Caribbean (Steeves et al. 2003), and colonies grouped into four major,
genetically differentiated populations; Caribbean, central Atlantic,
Indo-central Pacific, and eastern Pacific (Morris-Pocock et al. 2011). The
eastern Pacific population was found to be the most different genetically and
was estimated to have diverged from all other populations approximately one
million years ago (Morris-Pocock et al. 2011). These populations have diverged
because of a combination of physical barriers (the Isthmus of Panama and the
Eastern Pacific Basin) and a behavioral tendency in the Brown Booby to forage
closer to shore than other booby species (Steeves et al. 2003).
Table 1. Distinguishing characteristics of Brown Booby subspecies.
Copied from VanderWerf et al. (2023).
Character |
plotus |
leucogaster |
brewsteri |
nesiotes |
etesiaca |
Male
head color |
brown |
brown |
white
head and upper neck |
white
head and entire neck |
white
forehead |
Female
head color |
brown |
brown |
whitish
forehead |
whitish
forehead |
whitish
forehead |
Male
bill color |
bluish-yellow |
bluish-yellow |
grayish-blue |
grayish-blue |
grayish-blue |
Female
bill color |
yellow |
pinkish
yellow |
pinkish
yellow |
pinkish
yellow |
pinkish
yellow |
Ventral lesser wing coverts |
white |
white |
white
with brown bar |
white
with brown bar |
? |
New Information:
Three types of new information support
recognizing Brewster’s Booby as a separate species: 1) morphological data
demonstrating that males and females of the subspecies differ in additional
ways not previously recognized; 2) behavioral data on pairing patterns showing
that interbreeding between plotus and
brewsteri is rare despite increasing
sympatry; 3) information on behavioral ecology demonstrating that the
morphological differences between plotus
and brewsteri act as a reproductive
isolating mechanism that inhibits interbreeding. The information on behavioral
ecology is not that new, but its relevance to taxonomy does not seem to have
been considered previously.
1. Morphology. Descriptions of Brown Booby subspecies relied
primarily on the appearance of males and did not consider the appearance of
females. VanderWerf (2018) described differences between females of the
subspecies that can be used to identify them in the field: female S. l. brewsteri have a pinker bill and
paler forehead than female S. l. plotus.
Females can be distinguished as reliably as males of these subspecies, although
the characters used to identify females are less obvious. VanderWerf (2018) also
showed that the underwing coverts in both sexes of S. l. brewsteri are less extensively white than those of S. l. plotus.
I have unpublished data showing that iris color
and bill curvature also differ among Brown Booby subspecies, but I am still in
the process of collecting and analyzing these data. I do not think this
information about additional distinguishing characters is needed to assess the
taxonomy of Brown Boobies, but it will be useful in their identification.
2. Pairing Patterns. The Eastern Pacific Basin is
an enormous, island-free ocean area that for millennia has formed a physical
barrier to dispersal and promoted geographic differentiation of many seabirds,
including the Brown Booby (Avise et al. 2000, Steeves et al. 2003, Morris-Pocock
et al. 2011). Recently, Brown Boobies have been overcoming the barrier posed by
the Eastern Pacific Basin and have dispersed eastward and westward across the
Pacific. VanderWerf et al. (2008) documented an increasing number of S. l. brewsteri present and breeding in
the central Pacific, and Kohno and Mizutani (2011)
documented the occurrence and breeding of S.
l. brewsteri males on islands near Japan. Isla San Benedicto,
in the Revillagigedo Islands off the west coast of Mexico, was recolonized by
Brown Boobies following a volcanic eruption in 1952, and both plotus and brewsteri males are present and breeding on the island (Pitman and
Ballance 2002, Morris-Pocock et al. 2011). VanderWerf et al. (2023) showed that
the westward expansion of brewsteri
has continued, resulting in even greater sympatry between the subspecies. The
increasing sympatry of S. l. brewsteri
and S. l. plotus could result in gene
flow and erosion of differentiation between these forms if they interbreed.
VanderWerf et al. (2023) also collected data on
pairing patterns in locations where both forms were known to breed together.
Quantitative data showed pairing by S. l.
brewsteri and S. l. plotus was
primarily assortative and interbreeding was rare (Table 2). At Moku Mana, Maui, in 2021, there were fewer mixed pairs
(zero), than expected by chance (X2 = 18.00, df = 1, p < 0.001).
On Palmyra, there also were fewer mixed pairs than expected by chance (X2
= 181.1, df = 1, p < 0.001), although the sample size was small.
Anecdotal evidence also indicates that pairing
was primarily assortative, and that interbreeding was rare. On Wake Island in
2021, J. Gilardi observed 301 S. l. plotus pairs, six S. l.
brewsteri males, and one S. l.
brewsteri female, which was paired with one of the male S. l. brewsteri. The other five male S. l. brewsteri on Wake that year did
not attract a mate despite the presence of many unpaired S. l. plotus females. On Wake in 2022, J. Gilardi
observed that the brewsteri-brewsteri pair remained together and
raised another chick, but the other five brewsteri
males were unpaired. On Wake in 2023, J. Gilardi
observed seven male and four female brewsteri;
all 4 brewsteri females were paired
with brewsteri males, and the three
single brewsteri males built nests
but had no mate. On Moku Manu, Oahu, in May 2021, E.
VanderWerf observed 93 S. l. plotus
pairs and only one male and one female S.
l. brewsteri, which were paired with each other and had a large chick. In
September 2022, E. VanderWerf observed five S.
l. brewsteri females on Moku Manu, all of which
were unpaired. On Laysan, a nest with a male brewsteri and female plotus
was reported in 1998 (VanderWerf et al. 2008), but re-examination of photos
using identification criteria from VanderWerf (2018) revealed that the female
was S. l. brewsteri, representing
another instance in which a male and female brewsteri
paired with each other amid large numbers of male and female plotus. The only instances of
interbreeding occurred in locations where no female brewsteri were
present. On Midway, J. Plissner observed a male brewsteri x female plotus pair that raised a chick in 2020, when no female brewsteri were present. At Nakanokamishima Island, Japan, one brewsteri male paired and raised offspring with a plotus female from 2012-2014, but a
second brewsteri male was not able to
attract a mate despite frequent courtship attempts with plotus females (Kohno and Mizutani 2015).
Moku Mana Islet off the north coast of Maui is a particularly interesting
case. It was colonized by Brown Boobies recently, with the first nest
documented in 2004 by J. Penniman. In 2021, the island held twice as many S. l. brewsteri pairs as S. l. plotus pairs, with no mixed pairs.
This is the easternmost location in the Hawaiian Islands where Brown Boobies
breed, and the colonies were formed by individuals dispersing from the east (S. l. brewsteri) and west (S. l. plotus), much like the situation
on Isla San Benedicto (Pitman and Ballance 2002).
Table 2. Pairing patterns of Brown Boobies by
subspecies, including only cases in which the identity of both parents was
known. Copied from VanderWerf et al. (2023).
Location |
Year |
Male
plotus + female plotus |
Male
plotus + female brewsteri |
Male brewsteri
+ female plotus |
Male brewsteri
+ female brewsteri |
Palmyra
Atoll † |
2014 |
~200 |
1 |
0 |
8 |
Moku Mana |
2021 |
6 |
0 |
0 |
12 |
Moku Manu |
2021 |
93 |
0 |
0 |
1 |
Laysan |
1998 |
~70 |
0 |
0 |
1 |
Midway ‡ |
2020 |
15 |
NA |
1 |
NA |
Wake
Island |
2023 |
301 |
0 |
0 |
4 |
Nakanokamishima ‡ |
2009 |
~900 |
NA |
1 |
NA |
†
At Palmyra 30 nests were observed with at least one brewsteri parent, but some nests were attended by a single parent
and the identity of the mate was unknown.
‡ At Midway and Nakanokamishima
no female brewsteri were
present so there was no chance of a mixed pair.
3. Reproductive Isolating Mechanisms. Mate
choice and breeding biology of Brewster’s Booby have been studied extensively
in Mexico, and this literature is important for understanding the pairing
patterns observed in the central Pacific. Most importantly, López-Rull et al. (2016) showed that male S. l. brewsteri with their head painted brown to look like male S. l.
plotus were treated aggressively by their mate and that the level of
aggression was higher at a colony closer to the zone of overlap between the
forms. They concluded that female dislike of foreign males may function as a
reproductive barrier in populations close to contact zones, where the risk of
possibly maladaptive hybridization is highest. Montoya et al. (2018) showed
that the carotenoid-based greenish-blue color of the gular pouch of males was
energetically expensive to maintain, that its chroma peaked during courtship,
and that it may serve as a reliable signal of individual quality. Michael et
al. (2018) showed that color of the gular pouch in Brown Boobies in México was
related to foraging range and location, with individuals in poor body condition
constrained to low-cost, short-distance foraging trips closer to shore, where
they were unable to obtain the pelagic diet necessary for production of the
carotenoid-rich gular pouch ornament important in mate attraction.
Cumulatively, this research indicates that the morphological differences
between S. l. brewsteri and S. l. plotus act as an isolating
mechanism that inhibits interbreeding.
The morphological
and genetic differences between S. l.
brewsteri and other forms of the Brown Booby meet the standards for species
recognition under the typological (or morphological) and phylogenetic species
concepts, respectively (Mayr 2000, Wheeler 2000). The behavioral evidence
described in this study, increasing sympatry with primarily assortative mating
and rare interbreeding, meets the standards of the biological species concept
(Mayr 2000). Cumulatively, all three forms of evidence suggest that it would be
appropriate to consider Brewster’s Booby as a separate species again.
Occasional hybridization between S. l. brewsteri and S. l. plotus and the presence of some individuals of intermediate
appearance do not constitute evidence that they are conspecific. Similar
situations exist in two other pairs of booby species, specifically Blue-footed
Booby (S. nebouxii) and Peruvian
Booby (S. variegata), and Masked
Booby (S. dactylatra) and Nazca Booby
(S. granti). Blue-footed and Peruvian
boobies are largely allopatric, but breeding colonies occur together on two
islands off Peru, where mating is primarily assortative, with few instances of
hybridization, resulting in genetic differentiation and only limited
introgression (Figueroa 2004, Figueroa and Stucchi 2008, Taylor et al. 2012).
Nazca Booby was considered a subspecies of Masked Booby but was split into a
separate species based on morphological differences and assortative mating
(Pitman and Jehl 1998, AOU 2000), which subsequently was supported by evidence
of genetic differentiation (Friesen et al. 2002).
Part B. English name:
For the English common name, according to NACC
guidelines for English names, when a split restores species status and a
previously existing English name exists, that name would be resurrected. In
this case the name would have been Brewster’s Booby. However, given the recent
decision by AOS to change all eponymous common bird names, the name Brewster’s
Booby is no longer an option. Below I have listed several possible alternative
English common names, grouped by whether they are geographical or descriptive of
the bird. I have offered some discussion of each name, including the pluses and
minuses. My personal favorite is Cocos Booby and I recommend that as the new
English common name for. S. brewsteri.
GEOGRAPHIC NAMES
Cocos Booby. The rationale for this name is similar to that
of the Nazca Booby, which is named for a tectonic plate in the earth’s crust
that contains part of the range of that species. The Cocos Plate is located in
the eastern Pacific and is adjacent to and north of the Nazca Plate. The Cocos
Plate extends off the west coast of the Americas from Panama north to the
Mexican state of Jalisco (Figure 1). The volcanoes and earthquakes in western
Mexico and Central America are fueled by plate convergence and subduction of
the Cocos Plate under the North American and Caribbean plates. The Cocos Plate
is named for Cocos Island, which rides upon the plate and is the only part of
the plate above sea level. Cocos Island is an important nesting site for S. brewsteri, although the colonies
there are not among the largest of the species. One downside to this name is
that the Cocos Plate encompasses only a small portion of the geographic range
of S. brewsteri, although it contains
a larger proportion of the range than the Nazca Plate contains of the Nazca
Booby range. The parallel naming of Nazca Booby and Cocos Booby would provide a
logical, geographical rationale for these two species that overlap considerably
in range.
Mexican Booby. The name Mexican Booby would recognize that
much of the range of S. brewsteri
occurs in Mexico and Mexican Waters and that the type specimens were collected
in Mexico. Two drawbacks to this name are that 1) two subspecies that would be
included with S. brewsteri (S. b. nesiotes and S. b. etesiaca) are not found in Mexico, and 2) increasingly less
of the range of S. brewsteri will be
in Mexico if the current range expansion continues across the Pacific. These
same drawbacks also pertain to the name Cocos Booby. The name Mexican Booby
would provide historical context for the likely origin for many of these
dispersing birds.
Figure 1. Map of the earth’s tectonic plates, showing the
location of the Cocos Plate. From National Park Service: https://www.nps.gov/subjects/geology/plate-tectonics-evidence-of-plate-motions.htm
Tropical Eastern Pacific Booby. The Tropical
Eastern Pacific is a name applied to one of twelve marine realms that cover the
coastal waters and continental shelves of
the world's oceans as part of a global classification system called Marine
Ecoregions of the World (MEOW), which was devised by an international team,
including conservation organizations, academic institutions and
intergovernmental organizations (Spalding et al. 2007). It extends along the
Pacific Coast of the Americas, from the
southern tip of the Baja California Peninsula
in the north to northern Peru in the
south. The range of S. brewsteri
largely coincides with this geographic unit, though the species range does
extend farther to the north and south. Among geographic names this would be the
most geographically appropriate because it coincides most the with range of the
species. The main downside to this name is that it is long and cumbersome,
consisting of four words.
DESCRIPTIVE NAMES
White-headed Booby. The name White-headed Booby
is based on the most distinctive character of the species, the white head of
males, which was the character that seems to have contributed most to its
description as a separate species. However, this name has two significant drawbacks
that in my opinion disqualify it: 1) it would pertain only to males of the brewsteri and nesiotes forms, and not to males of etesiaca; and 2) it would not pertain to females of any form, and
thus would perpetuate the neglect of female appearance that has occurred
already.
Pale-headed Booby. Pale-headed Booby would be
preferable to White-headed Booby because it would apply to females and males of
all forms that would be included in S.
brewsteri. The main downside is that it seems a little bland.
Recommendation:
I recommend that S. l. brewsteri be split from other forms of the Brown Booby into a
separate species. This split has been mentioned previously (Schreiber and
Norton 2020), and the additional evidence described in this proposal
strengthens the rationale for the split. The scientific name for the re-split
species would revert to S. brewsteri,
as it was originally described by Goss (1888). Sula brewsteri should include all pale-headed subspecies that breed
in the eastern Pacific, including nesiotes
and etesiaca recognized by some
authors (Schreiber and Norton 2020). If subspecific status continues to be
recognized for these forms, they would become S. brewsteri nesiotes and S.
brewsteri etesiaca, respectively.
Although etesiaca males have a
pale, not white, head, etesiaca
females are similar to females in other forms of brewsteri, and genetically etesiaca
clearly grouped with other populations in the eastern Pacific (Steeves et al.
2003, Morris-Pocock et al. 2010). No changes are needed in taxonomic status or
nomenclature of the other Brown Booby subspecies, which are more similar to
each other morphologically and genetically (Morris-Pocock et al. 2011). Thus, S. l. plotus and S. l. leucogaster would remain subspecies of the Brown Booby.
For the English name, I recommend Cocos Booby,
for the reasons discussed above.
Note from Remsen on voting on Part B. A YES vote is for Cocos Booby,
the recommendation of the proposal and the unanimous choice of NACC, and a NO
is for some other name; please indicate if that is Brewster’s Booby, the
traditional name of the taxon, or some novel name.
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Eric A. VanderWerf,
April 2024
Additional notes on Part B – English name. When Remsen told VanderWerf
that SACC was not bound by the edict of the AOS Council on removing all
eponyms, VanderWerf responded by noting that he was not opposed to eponyms but
still preferred Cocos Booby for the following reasons: “I
prefer Cocos Booby for 3 reasons: 1) I like geographic names, and
this offers a nice parallel with Nazca Booby; 2) if the NACC also adopts the
split, then there would be a chance that the same English name, Cocos Booby,
would be recognized by both groups. Having different common names would be
confusing; and 3) the Spanish name, which has not been discussed and I don’t
know where/how/when that would happen, presumably would be Bobo Cocos, which
has a nice ring to it.”
Comments
from Remsen:
“Part
A: YES. The lack of non-assortative mating is striking especially because
reproductive isolating mechanisms in birds tend to be weakest when range
expansions bring taxa together that have had little previous contact. Also, note that the phenotypic differences
between Sula dactylatra and Sula granti roughly comparable to
those between brewsteri and leucogaster. Note also that there was no evidence for the
Peters-Wetmore lump of the two species.
The 4th edition of the AOU Check-list (1931) treated it as a
separate species, Brewster’s Booby (S. brewsteri) from Sula l.
leucogaster (White-bellied Booby), and the broadly defined species
treatment then appeared in the 5th edition (1957) based solely on
Peters’ and Wetmore’s treatment.
“Part
B: NO. I think Cocos is a much better name than any of the others in the
proposal for the biogeographic rationale outlined therein. Nevertheless, the title of VanderWerf et
al.’s paper makes it clear why Brewster’s is the better name in that that is
the name that seabird people use for the distinctive taxa of the eastern
Pacific. What better evidence do we need
than this that the name has about 130+ years of formal and informal association
with the eastern Pacific taxa? See also
the title of VanderWerf et al. (2008) above.
See also any of the 20+ papers, most of them published in The Auk,
that used “Brewster’s Booby”, as revealed by Google Scholar. Google search on “Brewster’s Booby” produces
934 hits. Brewster’s Booby was the name
used by the AOU (1931), where treated as a separate species. Hellmayr and Conover (1948) also used
Brewster’s Booby for S. l. brewsteri.
More recently, Howell and Zufelt (Oceanic
Birds of the World, 2019, Princeton Univ. Press) used “Brewster’s Brown Booby”
for S. l. brewsteri.
“Although Goss, who also described brewsteri,
made no attempt to justify that name and in fact did not make it clear that brewsteri
presumably honored “the” Brewster of ornithology, i.e. William Brewster. That was because it was so obvious that
William Brewster’s contributions to the avifauna of Baja California (e.g.,
“Birds of the Cape region of Lower California”, 1902, Bull. Museum Comp.
Zoology, 241 pp., and many additional papers, based on existing collections and
collections that he commissioned, but not on his own fieldwork) were so
important that no explanation was needed.
“William Brewster’s contributions to
ornithology go far beyond Baja California.
He was one of three founding members of the American Ornithological
Society itself (1873), and served as its president for three years. The AOS’s Brewster Medal is one of the three
highest awards it gives for research.
Brewster was a Fellow of the American Academy for Advancement of Science
(AAAS). He was the founder and a president of the Nuttall Ornithological Club,
the oldest ornithological society in the Western Hemisphere. He was the first president of Mass Audubon
from 1896 to 1913, and the major goal of that society was to restrict the
killing of wild birds and was a force behind passage of the Lacey Act of 1900
(which prohibits interstate commerce in wild birds killed illegally). Brewster was curator of birds at Harvard’s
Museum of Comparative Zoology from 1885 until his death in 1919. Henshaw’s 23 page memorial to Brewster in the Auk in 1920 outlines his many
additional contributions and personal attributes; Henshaw made it clear that Brewster was what
we would call a “good guy” nowadays:
‘He
was charitably disposed to all, and inclined to judge the delinquent leniently
and with forbearance. He never spoke ill of any man. He was generously
inclined, and, within his means, gave freely to those less fortunate than
himself, though of his beneficence he said nothing, preferring that it should remain unknown.
‘He
was absolutely truthful, habitually refrained from all exaggeration, and
falsehood and evasion were foreign to his nature. As he was sincere and
truthful, so was he honorable and pure minded, and his conversation reflected
the thoughts and imaginings of a pure soul.’
“Some tidbits gleaned from these and other
sources: All three of his siblings died in childhood; their early deaths
evidently inspired the poem The Open Window, by Henry Wadsworth
Longfellow, one of the Brewster family’s neighbors. Brewster had some sort of vision problem as a
child, but that seems to have passed as he became an adult. His extensive field notes have been digitized
and are online, and browsing through these, it is clear that Brewster was not
only a keen observer of birds but really loved them. Actually watching birds and describing their
behavior was his passion, and in this way seemed ahead of his time despite what
must have been primitive optics. Perhaps
in compensation, he had a reputation for extremely sharp hearing and ability to
identify birds at a distance by voice to the extent that Henshaw considered him
supremely talented:
‘His hearing was
extraordinarily acute, and his ability to recognize the notes of birds at a
distance and amid other and confusing sounds was little less than marvelous,
and far exceeded that of any one I ever knew.’
“His 38 years of fieldwork at Lake Umbagog, on the Maine-New Hampshire border, produced some
legendary observations, often from his canoe, to the point that Robert Stymiest published excerpts as a paper in the Bird Observer in 2004. At Lake Umbagog, he
made the first detailed observations
of the nesting behavior of the Philadelphia Vireo, as just one of his
many contributions. He was also one of
many famous naturalists who made extensive observations in the Concord,
Massachusetts, and kept copious field notes on his experiences there; in fact,
in 1937, a 300 page book of
selections from his Concord journals was published.
Brewster was also interested in bird migration, and actually spent 6
weeks in Fall 1885 at a lighthouse in the Bay of Fundy do study the behavior of
migrating birds. The paper he published
on these observations was a classic of the era.
“I herein take the opportunity to make some
positive remarks on eponymous English names.
Brewster’s case, in my opinion, provides a strong example of the value
of eponyms. Yes, many of these founders
of American ornithology are memorialized in other ways, including scientific
names. However, most birders and even
many professional ornithologists have a weak knowledge of scientific names, and
even fewer are inclined to delve into the general history of ornithology in
North America on their own. An English
name, however, gets the attention of every bird person who uses it. Most will never take the time to read about
these people, but those who do will hopefully be inspired and will be reminded
that we got where we are today in our understanding of birds through the work
of those who preceded us. Knowing that we
humans are instinctively interested in stories about other humans, I doubt that
I am the only one inspired by the stories of people like Brewster. Some of you may know why I have a special admiration
for Brewster, but I hope all of you will appreciate this accomplishments and
the reverence in which he was held by his peers. Contrast the window into ornithology opened
by “Brewster’s Booby” compared to the value of a name like “Brown Booby,” its
sister species. Yes, Brown Booby is an
excellent descriptive name. It is indeed
a brown booby, brownest of the genus.
But that’s where the value ends.
There is no depth, no cachet, no inspiration. In my opinion, I think that having a tiny
percentage of English names that honor contributors to ornithology acknowledges
that we did not get here on our own and provides potential inspiration for
others to contribute to ornithology and especially in a case like Brewster to
appreciate birds more deeply.
“Additional points: one problem with
Cocos is that the name is clearly associated with three endemics of Cocos
Island (Cocos Cuckoo, Cocos Flycatcher, Cocos Finch) and thus the natural
implication of the name “Cocos Booby” is that it is another island endemic. Few people are aware of the name Cocos Plate,
and so confusion will be inevitable. By
the way, there is no need to discuss adding group names in this case, e.g.
“Cocos Brown-Booby” etc., because our guidelines indicate that there is no need
for that if two species previously split, then lumped, and then re-split ---
the original species treatment used Brewster’s Booby for S. brewsteri
(and White-bellied Booby for S. leucogaster). Using White-bellied Booby for narrowly
defined S. leucogaster also should be discussed, as recommended in our
guidelines on English names because it calls attention to the species split and
restores a historical name used in much literature prior to 1957.”
Comments from Don Roberson (voting for Claramunt):
YES on Cocos Booby. Although "Brewster's
Booby" would have been okay with me, some people disfavor eponymous common
names, so a different English name is fine at this point in time. The genus Sula currently has a nice set
of English names: Red-footed, Blue-footed, Brown, Peruvian, Masked, and Nazca.
[in the Sulidae, only the monotypic genus Papasula has an eponymous
name, but it resides far from the New World.]
“Traditionally,
the long-standing set of the five basic Sula boobies were Red-footed,
Blue-footed, Brown, Peruvian, and Masked. All are short, distinctive, and
memorable -- 4 are based on plumage and/or soft-parts color, and one is named
for the Peruvian Current where it occurs. Red-footed and Blue-footed are surely
among the "really good English names" for those species. Brown and
Masked are accurate and serviceable. Then came the first split in Sula,
and I was delighted when the authors of the taxonomic paper (Pitman & Jehl
1998) concluded with this line: "As a
common name for Sula granti we propose Nazca Booby, which
recognizes that the current breeding range and probably evolutionary history of
this species is closely associated with the Nazca Crustal Plate."
“This was a great English name -- short, very memorable, reasonable
accurate, and innovative. In 1989, when I spent 4 months in the eastern
tropical Pacific on a NOAA ship, with Bob Pitman on a sister ship on that
cruise, Bob asked me to take notes on the juvenal "Masked" Boobies
when we went through the Galapagos, which he used in writing his 1998 paper
[later, I wrote a paper on ID issues in Masked & Nazca Boobies.] On that
same cruise, we had the good fortune to visit Isla del Coco [Cocos Island, off
Costa Rica] and even land on the island. My notes also mention a "breeding
colony on Nuez I., where Gary Fredrichsen
saw fledglings" of brewsteri Brown Booby while I was on Cocos
itself (Nuez is a tiny islet in Chatham Bay; we also
scoped it with the ship's Big Eyes).
“Now, we have an opportunity to give S. brewsteri another
excellent English name: Cocos Booby. It parallels the name Nazca Booby nicely.
Neither name includes all the breeding range of the Sula involved, let
alone its at-sea distribution, but Cocos is a core
breeding location, well represents core at-sea range, and does so better than
the Nazca Plate did for Nazca Booby. It is really a fine choice: short, very
memorable, reasonable accurate, and innovative in parallel with Nazca. While it
is useful to name local resident landbird endemics for the island on which they
occur (e.g., Cocos Finch), it is also appropriate to name a seabird after the
tectonic plate which covers a good portion of both its breeding and its pelagic
range, postulating, as did Pitman & Jehl, that it is likely that the
"evolutionary history of this species is closely associated with the Cocos
Crustal Plate."
“None of the other options are as attractive. "White-headed"
and "Pale-headed" are rather boring, do not accurately describe all
subspecies, and focus only on adult male plumages but would not be accurate for
well over half of the birds encountered (females, sub-adults, and juvs).
"Tropical Eastern Pacific Booby" is a jaw-breaker, not significantly
more accurate, and would break the string of having the names of all Sula
boobies be short, distinctive, and punchy. Finally, "Mexican Booby"
is misleading is multiple ways -- Mexico (including the western coast of
Mexico) has multiple species of boobies, but more importantly, the eastern
coast of Mexico will have a Brown Booby from the Gulf that is not brewsteri,
so a "Mexican Booby" would not even include the Caribbean coast, with
its entirely different type of "Brown Booby", adding to confusion.
“VanderWerf et al. (2023) does point out that there are four major
lineages in Brown Booby: Caribbean, central Atlantic, Indo-central Pacific, and
eastern Pacific. Some have suggested that all might be elevated to species
level, and that in doing so, a hyphenated English name -- Brown-Booby -- should
be preceded by a modifier to create, say, Caribbean Brown-Booby, Atlantic
Brown-Booby etc. SACC has adopted this sort of scheme multiple times, but
generally in complex situations (e.g., the Trogonidae, Thamnophilidae). The Sula
boobies are currently just 7 species (with brewsteri) and only 10
species if the other 3 Brown Booby lineages were to be split, and even the
entire Sulidae would be just 14 species. I don't think we need hyphenated
English names is this relatively small group of Sulids, and to do so would
create long names which are neither short, memorable, or punchy. But even if
later taxonomic changes might be made, Cocos Booby or "Cocos
Brown-Booby" would still be the best choice, in my opinion, for the
eastern Pacific taxa.
“Citation: Pitman & Jehl (1998) Geographic variation and
reassessment of species limits in the "Masked " boobies of the
eastern Pacific Ocean. Wilson Bull 110: 155-170.”