Philippine creeper
Encyclopedia
The Philippine creepers or rhabdornises are small passerine bird
s. They are endemic
to the Philippines
. The group contains a single genus Rhabdornis with three species. They do not migrate
, other than to make local movements.
There are three species
in the single genus
Rhabdornis:
s (Certhiidae). They have thin pointed down-curved bills, which they can use to extricate insects from bark, but they have brush-like tongues, which enable them to also feed on nectar. Their behaviour is said to resemble that of tits (to which they are certainly not closely related) more than the treecreepers. Nests are tree crevices.
The placement of genus Rhabdornis in a family
of its own (Rhabdornithidae Greenway, 1967) is not accepted by all authorities, and it is sometimes placed in Certhiidae or Timaliidae. The German name, Trugbaumläufer ("false treecreepers"), reflects this uncertainty. More recently, Zuccon et al. 2006 place them in a basal clade
inside the starlings in the family Sturnidae. Their closest allies seem to be a number of quite plesiomorphic starling lineages mainly from the Asian-Pacific region (such as myna
s), so this placement seems as plausible as any other. Judging from biogeography
alone, the treecreepers are indeed far less likely to be related to the Philippine creepers than starlings or timaliids, as neither the Certhiidae nor their close relatives expanded into the Wallacea
whereas the latter did. Note also the general rarity of small woodpeckers on the Philippines, implying that any bird lineage that would happen to adapt to the same ecological niche
was likely to be successful.
Nonetheless, the placement with the starlings requires confirmation. As notoriously confounded by convergent evolution
as Philippine creeper anatomy
is, the scenario of Zuccon et al. requires the underlying plesiomorphies closer to those present in starlings and thrashers than to those retained in treecreepers and wren
s, and vice versa as regards synapomorphies. This has not been tested; in the meantime, it may be noted that the color pattern of Rhabdornis is more similar to that of some Aplonis
- a member of the group of starlings supposedly most close to the Philippine creepers - than to that of treecreepers. Both Philippine and treecreepers are cryptic
in adaptation
to their tree-creeping lifestyle, but this is achieved with a very different camouflage
pattern in either. Additionally, they are very distant even among starlings (Zuccon et al. 2006: 340) and may in the end be maintained as a family on their own. The Australian treecreepers (Climacteridae), meanwhile, are an entirely unrelated family of passerine birds which is actually close to bowerbird
s (Ptilonorhynchidae).
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
s. They are endemic
Endemism in birds
An endemic bird area is a region of the world that contains two or more restricted-range species, while a "secondary area" contains one or more restricted-range species. Both terms were devised by Birdlife International....
to the Philippines
Philippines
The Philippines , officially known as the Republic of the Philippines , is a country in Southeast Asia in the western Pacific Ocean. To its north across the Luzon Strait lies Taiwan. West across the South China Sea sits Vietnam...
. The group contains a single genus Rhabdornis with three species. They do not migrate
Bird migration
Bird migration is the regular seasonal journey undertaken by many species of birds. Bird movements include those made in response to changes in food availability, habitat or weather. Sometimes, journeys are not termed "true migration" because they are irregular or in only one direction...
, other than to make local movements.
There are three species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
in the single genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
Rhabdornis:
- Stripe-headed Creeper, Stripe-headed Rhabdornis or Stripe-sided Rhabdornis, Rhabdornis mystacalis
- Long-billed Creeper, Long-billed Rhabdornis or Grand Rhabdornis, Rhabdornis grandis
- Stripe-breasted Creeper, Plain-headed Creeper or Stripe-breasted Rhabdornis, Rhabdornis inornatus
Description, systematics and taxonomy
The Philippine creepers are similar in appearance to treecreeperTreecreeper
The treecreepers are a family, Certhiidae, of small passerine birds, widespread in wooded regions of the Northern Hemisphere and sub-Saharan Africa. The family contains ten species in two genera, Certhia and Salpornis...
s (Certhiidae). They have thin pointed down-curved bills, which they can use to extricate insects from bark, but they have brush-like tongues, which enable them to also feed on nectar. Their behaviour is said to resemble that of tits (to which they are certainly not closely related) more than the treecreepers. Nests are tree crevices.
The placement of genus Rhabdornis in a family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
of its own (Rhabdornithidae Greenway, 1967) is not accepted by all authorities, and it is sometimes placed in Certhiidae or Timaliidae. The German name, Trugbaumläufer ("false treecreepers"), reflects this uncertainty. More recently, Zuccon et al. 2006 place them in a basal clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
inside the starlings in the family Sturnidae. Their closest allies seem to be a number of quite plesiomorphic starling lineages mainly from the Asian-Pacific region (such as myna
Myna
The myna is a bird of the starling family . This is a group of passerine birds which occur naturally only in southern and eastern Asia...
s), so this placement seems as plausible as any other. Judging from biogeography
Biogeography
Biogeography is the study of the distribution of species , organisms, and ecosystems in space and through geological time. Organisms and biological communities vary in a highly regular fashion along geographic gradients of latitude, elevation, isolation and habitat area...
alone, the treecreepers are indeed far less likely to be related to the Philippine creepers than starlings or timaliids, as neither the Certhiidae nor their close relatives expanded into the Wallacea
Wallacea
Wallacea is a biogeographical designation for a group of Indonesian islands separated by deep water straits from the Asian and Australian continental shelves. Wallacea includes Sulawesi, the largest island in the group, as well as Lombok, Sumbawa, Flores, Sumba, Timor, Halmahera, Buru, Seram, and...
whereas the latter did. Note also the general rarity of small woodpeckers on the Philippines, implying that any bird lineage that would happen to adapt to the same ecological niche
Ecological niche
In ecology, a niche is a term describing the relational position of a species or population in its ecosystem to each other; e.g. a dolphin could potentially be in another ecological niche from one that travels in a different pod if the members of these pods utilize significantly different food...
was likely to be successful.
Nonetheless, the placement with the starlings requires confirmation. As notoriously confounded by convergent evolution
Convergent evolution
Convergent evolution describes the acquisition of the same biological trait in unrelated lineages.The wing is a classic example of convergent evolution in action. Although their last common ancestor did not have wings, both birds and bats do, and are capable of powered flight. The wings are...
as Philippine creeper anatomy
Anatomy
Anatomy is a branch of biology and medicine that is the consideration of the structure of living things. It is a general term that includes human anatomy, animal anatomy , and plant anatomy...
is, the scenario of Zuccon et al. requires the underlying plesiomorphies closer to those present in starlings and thrashers than to those retained in treecreepers and wren
Wren
The wrens are passerine birds in the mainly New World family Troglodytidae. There are approximately 80 species of true wrens in approximately 20 genera....
s, and vice versa as regards synapomorphies. This has not been tested; in the meantime, it may be noted that the color pattern of Rhabdornis is more similar to that of some Aplonis
Aplonis
Aplonis is a genus of starlings. These are essentially island species of Indonesia, Oceania and Australasia, although some species’ ranges extend to the Malay Peninsula, southern Vietnam and northeastern Queensland. The typical adult Aplonis starling is fairly uniformly plumaged in black, brown or...
- a member of the group of starlings supposedly most close to the Philippine creepers - than to that of treecreepers. Both Philippine and treecreepers are cryptic
Crypsis
In ecology, crypsis is the ability of an organism to avoid observation or detection by other organisms. It may be either a predation strategy or an antipredator adaptation, and methods include camouflage, nocturnality, subterranean lifestyle, transparency, and mimicry...
in adaptation
Adaptation
An adaptation in biology is a trait with a current functional role in the life history of an organism that is maintained and evolved by means of natural selection. An adaptation refers to both the current state of being adapted and to the dynamic evolutionary process that leads to the adaptation....
to their tree-creeping lifestyle, but this is achieved with a very different camouflage
Camouflage
Camouflage is a method of concealment that allows an otherwise visible animal, military vehicle, or other object to remain unnoticed, by blending with its environment. Examples include a leopard's spotted coat, the battledress of a modern soldier and a leaf-mimic butterfly...
pattern in either. Additionally, they are very distant even among starlings (Zuccon et al. 2006: 340) and may in the end be maintained as a family on their own. The Australian treecreepers (Climacteridae), meanwhile, are an entirely unrelated family of passerine birds which is actually close to bowerbird
Bowerbird
Bowerbirds make up the bird family Ptilonorhynchidae. The family has 20 species in eight genera. These are medium-sized passerines, ranging from the Golden Bowerbird to the Great Bowerbird...
s (Ptilonorhynchidae).
External links
- Don Robertson's Bird Families of the World: Rhabornises. Contains photos of all 3 species. Version of 2006-JAN-25. Retrieved 2007-JUL-20.
- Flickr Field Guide: Birds of the World: Photo of Rhabdornis mystacalis. Retrieved 2007-JUL-19.