Nest attendance by tropical and temperate passerine birds: Same constancy, different strategy

Research output: Contribution to journalArticle


Parental care in birds varies among species and geographic regions. Incubation behavior influences embryonic development rate and varies substantially among species. We studied attendance at the nest by videoing nests or collecting data from the literature for 112 species in north temperate and lowland tropical sites, then associated patterns of incubation on- and off-bouts with species and environmental traits. Songbirds nesting at low elevations incubate their eggs for an average of 74.1% (±12.9 SD, n = 60 species) of the time in temperate regions and 71.0% (±12.2 SD, n = 52 species) in tropical regions during daylight hours, and 84.3% (±8.2 SD) and 85.3% (±6.2 SD), respectively, of each 24-hr cycle. While these attendance percentages do not differ significantly between latitudes, our data also show that lowland tropical songbirds make fewer visits to the nest and, consequently, have longer on-bouts and off-bouts during incubation. This pattern in attendance reflects a latitudinal contrast in parental care strategy, where lowland tropical birds reduce visits to the nest by increasing on- and off-bout lengths while maintaining the same proportion of time spent incubating their eggs (constancy). Similar constancy across latitude suggests that tropical and temperate birds may be similarly constrained to maintain elevated egg temperatures for normal embryo growth. The different attendance strategies adopted in each region may reflect differences in ambient temperature, adult foraging time, and nest predation rate. Consistently warm ambient temperatures likely allow tropical birds to take longer off-bouts, and thereby to reduce activity around the nest, compared to temperate birds.


  • Suzanne H. Austin
  • William Douglas Robinson
  • Vincenzo A. Ellis
  • Tara Rodden Robinson
  • Robert E. Ricklefs
External organisations
  • Oregon State University
  • University of Missouri-St. Louis
  • University of Delaware
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Evolutionary Biology


  • incubation, latitudinal gradient, life-history evolution, parental care, passerine birds
Original languageEnglish
Pages (from-to)13555-13566
Number of pages12
JournalEcology and Evolution
Issue number23
Early online date2019 Nov 21
Publication statusPublished - 2019 Dec
Publication categoryResearch