Tanager Taxonomy and Geography Exercise

The group of birds known as tanagers consists of more than 240 species. Confined to the Western Hemisphere, they are primarily Neotropical in distribution. Small (most are about 5 inches long), fruit- and insect-eating birds, tanager males are often brilliantly colored; thus, tanagers comprise a high percentage of the more visible birds in the tropical forests and shrub lands of South America. The Andes are an area of high tanager species richness.

Below are partial lists of tanager species known to occur at two sites on either side of the Andes, at the approximate latitude of Quito, Ecuador. These data are from Birding Ecuador (2nd edition), by Clive Green, 1996.

DATA:

I. Mindo, western slopes of Andes, elev. = 6,000 ft.

Common name

Scientific Name
Fawn-breasted Tanager Pipraeidea melanonota
Glistening-green Tanager Chlorochrysa calliparaea
Rufous-throated Tanager Tangara rufigula
Golden Tanager Tangara arthus
Silvery-throated Tanager Tangara icterocephala
Saffron-crowned Tanager Tangara xanthocephala
Flame-faced Tanager Tangara parzudakii
Metallic green Tanager Tangara labradorides
Blue-necked Tanager Tangara cyanicollis
Golden-hooded Tanager Tangara larvata
Golden-naped Tanager Tangara ruficervix
Bay-headed Tanager Tangara gyrola
Beryl-spangled Tanager Tangara nigroviridis
Black-capped Tanager Tangara heinei
Blue-winged Mountain Tanager Anisognathus somptuosus
Black-chinned Mountain Tanager Anisognathus notabilis
Swallow Tanager Tersina viridis
Blue-Gray Tanager Thraupis episcopus
Palm Tanager Thraupis palmarum
Bright-rumped Tanager Rampholcelus flammigerus
Summer Tanager Piranga rubra
White-winged Tanager Piranga leucoptera
White-lined Tanager Tachyphonus rufus
White-shouldered Tanager Tachyphonus luctuosus
Ashy-throated Bush Tanager Chlorospingus canigularis
Yellow-throated Bush Tanager Chlorospingus flavigularis
Dusky-throated Bush Tanager Chlorospingus semifuscus
Grass-Green Tanager Chlorornis riefferii

 

II. San Isidro, eastern flanks of Andes, elev. = 6,500 ft.

Common name

Scientific Name
Fawn-breasted Tanager Pipraeidea melanonota
Saffron-crowned Tanager Tangara xanthocephala
Golden-eared Tanager Tangara chrysotis
Flame-faced Tanager Tangara parzudakii
Beryl-spangled Tanager Tangara nigroviridis
Blue-and-black Tanager Tangara vassorii
Black-capped Tanager Tangara heinei
Golden-crowned Tanager Iridosornis rufivertex
Blue-winged Mountain Tanager Anisognathus soptusosus
Blue-Gray Tanager Thraupis episcopus
Summer Tanager Piranga rubra
White-capped Tanager Sericossypha albocristata
Common Bush Tanager Chlorospingus ophthalmicus

QUESTIONS:

A. Distinguishing genus from species

Assuming that these samples are representative of the distribution of tanagers with respect to the Andes, answer the following questions:

  1. What is the total number of tanager species occurring at the 6,000-6,500 foot level in the Andes of central Ecuador?
  2. How many genera occur at this elevation?
  3. How many species are restricted in their distribution to the western side of the Andes?
  4. How many genera are restricted to the western side?
  5. How many species are restricted in their distribution to the eastern side of the Andes?
  6. How many genera are restricted to the eastern side?
  7. How many genera are found on both sides?
  8. List the species that are found on both sides. Use scientific names.
  9. Which is the most species-rich genus?
  10. Name one monospecific tanager genus (based on the data above).
  11. Name a congener of the Dusky-throated Bush Tanager, Chlorospingus semifuscus.
  12. The Scarlet Tanager (Piranga olivacea), shown at the top of the page, is one of four tanager species that occur as summer residents in the United States. What are the other three? ANSWER. How many genera are represented in the US?

B. Taxonomic levels and biogeographic patterns

Consider the tanagers as a whole as a family [Until recently, indeed, they were so classified and were put in the family Thraupidae. Today, most taxonomists place them as a lineage or subfamily within the large family Emberizidae, which contains all songbirds with 9 primary feathers--the tenth being greatly reduced--and includes, along with the tanagers, the wood warblers (subfamily Parulidae), cardinals, sparrows, and buntings (subfamily Fringillidae).]

  1. What would a general distribution map of the tanager family look like?
  2. What would a general distribution map of the genus Tangara look like?
  3. What would a general distribution map of the species Tangara parzudakii look like? Of T. larvata?
  4. Make a general statement relating taxonomic level to geographic distribution pattern.
  5. Link to USGS's Northern Prairie Wildlife Research Center, where you will find maps of the Ranges of North American Breeding Birds. Scroll down the page to the tanagers. Look at the most recent distribution maps for three of the four tanager species occurring in the US.

Return to Biogeography Course home page

ANSWER: Scarlet Tanager (Piranga olivacea). Summer Tanager (P. rubra), Hepatic Tanager (P. flava), and Western Tanager (P. ludoviciana). Check a good field guide to the birds of North America for pictures and distribution maps.

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