Tanager

Tanagers
Grass-green Tanager, Chlorornis riefferii
Grass-green Tanager, Chlorornis riefferii
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Passeriformes
Suborder: Passeri
Family: Thraupidae
Genera

many: see text

The tanagers are a family, Thraupidae, of birds in the order Passeriformes. The family has an American distribution.

There were traditionally about 240 species of tanagers, but the taxonomic treatment of this family's members is currently in a state of flux. As more of these birds are studied using modern molecular techniques it is expected that some genera may be relocated elsewhere. Already the Euphonias and chlorophonias, which were once considered part of the tanager family, are now treated as members of Fringillidae, in their own subfamily (Euphoniinae). Likewise the genera Piranga, Chlorothraupis, and Habia appear to be related to members of the Cardinal family[1], and may soon be reassigned by the AOU.

Contents

Description

Tanagers are small to medium-sized birds. The shortest-bodied species, the White-eared Conebill, is 9 cm (3.8 in) long and weighs 7 grams, barely smaller than the Short-billed Honeycreeper. The longest, the Magpie Tanager is 28 cm (11 in) and weighs 76 grams (2.7 oz). The heaviest is the White-capped Tanager which weighs 114 grams (4 oz) and measures about 23 cm (8.7 in). Both sexes are usually the same size and weight. Tanagers are often brightly colored, but some species are black and white. Birds in their first year are often duller or a different color altogether. Males are typically more brightly coloured than females.

Most tanagers have short, rounded wings. The shape of the bill seems to be linked to the species' foraging habits.

Distribution

Tanagers are restricted to the New World and mainly to the tropics. About 60% of tanagers live in South America, and 30% of these species live in the Andes. Most species are endemic to a relatively small area. 18 species live in North America and Central America year round. 4 species are migratory, breeding in North America. They are the Scarlet Tanager, Western Tanager, Hepatic Tanager and the Summer Tanager. Recent molecular evidence indicates these 4 migratory species may be more closely related to the family Cardinalidae.

Behaviour

Most tanagers live in pairs or in small groups of 3-5 individuals. These groups may consist simply of parents and their offspring. Birds may also be seen in single species or mixed flocks. Many tanagers are thought to have dull songs, though some are elaborate.

Diet

Tanagers are omnivorous, and their diet varies from genus to genus. They have been seen eating fruits, seeds, nectar, flower parts and insects. Many pick insects off branches. Other species look for insects on the underside of leaves. Yet others wait on branches until they see a flying insect and catch it in the air. Many of these particular species inhabit the same areas, but these specializations alleviate competition.

Reproduction

The breeding season begin in March through until June in temperate areas and in September through October in South America. Some species are territorial while others build their nests closer together. There is little information on tanager breeding behavior or whether they are monogamous or polygamous. Males show off their brightest feathers to potential mates and rival males. Some species' courtship rituals involve bowing and tail lifting.

Most tanagers build cup nests on branches in trees. Some nests are almost globular. Entrances are usually built on the side of the nest. The nests can be shallow or deep. The species of the tree they choose to build their nest in and the nest's position varies among genera. Most species nest in an area hidden by very dense vegetation. There is still no information on the nests of some species.

The clutch size is 3–5 eggs. The female incubates the eggs and builds the nest, but the male may feed the female while she incubates. Both sexes feed the young. Five species have helpers assist in feeding the young. These helpers are thought to be the previous year's nestlings.

Systematics

Phylogenetic studies suggest the true tanagers form three main groups two of which consist of several smaller, well-supported clades.[2] The list below is an attempt using information gleaned from the latest studies to organise them into coherent related groups, and as such may contain groupings not yet accepted by or are under review by the various ornithological taxonomy authorities.[3]

Group 1

Mainly dull-coloured forms

Slaty Finch, Haplospiza rustica

a) Conebill and flowerpiercer group (Also contains Haplospiza, Catamenia, Acanthidops, Diglossa, Diglossopis, Phrygilus and Sicalis[4] traditionally in the Emberizidae)[5] This group despite having a rather varied bill morphology shows marked plumage similarities. Most are largely grey, blue, or black, and numerous have rufous on the underparts:

b) True seedeaters. Traditionally placed in Emberizidae. These genera share a particular foot-scute pattern which suggests that they may form a monophyletic group[9]:

Male Variable Seedeater, Sporophila corvina

c) "Yellow-rumped" clade[12]:

d) "Crested" clade (Also contains Coryphospingus & Volatinia traditionally placed in the Emberizidae):

e) "Blue Finch" clade. Relationships within Thraupidae uncertain but may be related to "Poospiza" clade[13]:

f) The "Poospiza" clade - a diverse but close-knit group containing both warbler and finch-like forms:

Brazilian Tanager, Ramphocelus bresilius

g) Grass & Pampa-finches. Relationships within Thraupidae uncertain but together form a well-supported clade[17]:

h) A miscellaneous and likely polyphyletic group of unplaced "tanager-finches" (which may or may not include the species called Tanager-finch) whose members when studied will no doubt be relocated to other clades:

i) Basal forms in group 1:

Group 2

"Typical" colourful Tanagers

Diversity of Darwin's finches

a) Tropical canopy tanagers:

b) The "Tholospiza" - Darwin's finches, grassquits, atypical honeycreepers and some seedeaters.[20] The finch-like forms in this clade were formerly classified in the Emberizidae:

Green-and-gold Tanager, Tangara schrankii

c) Mountain tanagers:

Blue-gray Tanager, Thraupis episcopus

d) Typical tanagers:

e) Typical multicoloured tanagers (includes Paroaria traditionally placed in either Emberizidae or Cardinalidae):

f) Green & Golden-collared Honeycreepers[23]:

g) Typical honeycreepers and relatives[24]<refSee Klicka et al (2007) - may be closer to group 1</ref>:

h) Basal lineages within group 2:

Green Honeycreeper, Chlorophanes spiza

Group 3

Saltators

Thraupidae incertae sedis

The Western Tanager (Piranga ludoviciana) seems to be closer to cardinals

Recently split from Thraupidae

Related to Arremonops and other american sparrows in Emberizidae:

Related to the cardinals in Cardinalidae[29]:

Footnotes

  1. ↑ Yuri & Mindell (2002)
  2. ↑ Fjeldså & Rahbek (2006) & Klicka et al (2007)
  3. ↑ See http://www.museum.lsu.edu/~Remsen/SACCBaseline.html
  4. ↑ Burns et al (2003) & Klicka et al (2007)
  5. ↑ See Webster & Webster (1999). If the presence of a free lacrimal bone as found in Haplospiza, Acanthidops, and two of the three Catamenias has any phylogenetic significance then this clade may also include several other "tanager-finches" that share this feature
  6. ↑ Klicka (2007)
  7. ↑ Webster & Webster (1999) & Klicka et al (2007). Probably polyphyletic
  8. ↑ Klicka et al (2007)
  9. ↑ Clark (1986)
  10. ↑ See Lijtmaer et al (2004) & Robbins et al (2005). Polyphyletic. Members of this genus are paraphyletic with various members of Sporophila
  11. ↑ See Robbins et al (2005). This species is nested within a group containing both Sporophila and Oryzoborus
  12. ↑ Burns et al (2003)
  13. ↑ (See below: Group 1f)
  14. ↑ Klicka et al (2007). This species formerly placed near Passerina in the Cardinalidae is related to Phrygilus alaudinus a tanager-finch
  15. ↑ http://www.zoonomen.net/cit/RI/Genera/RIGenAZ.html
  16. ↑ Klicka et al (2007). This genus is very likely polyphyletic within its clade
  17. ↑ Klicka et al (2007)
  18. ↑ Ridgely & Tudor (1989) p.472
  19. ↑ Klicka et al (2007). Some members of this genus paraphyletic with respect to certain Tangara
  20. ↑ See Burns et al (2002) for the circumscription of this group the "domed nest clade" or "Tholospiza".
  21. ↑ See Burns et al (2002). Exact affinities uncertain but probably sister species to Tiaris olivacea in the "Tholospiza"
  22. ↑ See http://www.museum.lsu.edu/~Remsen/SACCBaseline10.html Apparently close to mountain-tanagers Dubusia and Delothraupis
  23. ↑ See Burns et al (2003) for close relationship of these species
  24. ↑ See Burns et al (2003)
  25. ↑ 25.0 25.1 Klicka & Spellman (2007)
  26. ↑ See http://www.museum.lsu.edu/~Remsen/SACCBaseline10.html
  27. ↑ Klicka et al (2007). Apparently closest to Saltator atricollis and this species may require moving to Saltatricula
  28. ↑ See http://www.museum.lsu.edu/~Remsen/SACCBaseline10.html. May be related to the emberizine genus Atlapetes
  29. ↑ See http://www.museum.lsu.edu/~Remsen/SACCBaseline11.html

References

External links

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