Desert vs Rambur's Forktail

Two widespread species of forktails in Arizona are the Desert Forktail and the Rambur’s Forktail. Both species are often encountered at a same location. To separate males of the two species, focus on the thoracic stripes and the shape of the abdominal black stripes.

In the hand, the shape of male appendages is characteristic of each species. See photos at the end of each species’ photo page.

As in other forktail species, females come in two forms: Heteromorph and andromorph (= male-like). The color pattern of mature of andromorph females is very similar to that of conspecific mature males.

Male Comparison

Thorax

  • Desert Forktail: antehumeral stripe relatively wide, often yellowish
  • Rambur’s Forktail: antehumeral stripe narrow

Abdomen

  • Desert Forktail: black markings on abdominal segments 3-6 are torpedo-shape
  • Rambur’s Forktail: black markings on abdominal segments 3-6 of uniform width

Lateral views of the head/thorax and middle abdominal segments of the Desert and Rambur's Forktails, AZ.

Appendages

  • Desert Forktail: paraprocts relatively long with upturned tips
  • Rambur’s Forktail: paraprocts short and straight.

Lateral views of the appendages of the male Desert and Rambur's Forktails, AZ.

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