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Sterna hirundo

(Common Tern)

Overview:

This migratory species breeds in inland areas of the Northern Hemisphere and winters along the coasts of South America, Africa, India, and Australia. The sexes are similar.

Conservation Status

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Population Analysis

  • For the 56,576 species in the Class Aves (Birds), we average 371.87 observations each in our database; for the Common Tern, we have 2,186 observations. Compared to other species in this Class, this species is somewhat common.
  • A two-sample t-test can be used to determine whether the trend in observations of the Common Tern is the same as the trend in observations of Aves. Is this species just as common, as a proportion of all observations, as it once was? The answer is no, changes in observation rate of this species significantly differ from changes in observation rate of its Class. (t=46.335, p<0.001)
  • How do observation rates of the Common Tern differ from those of Aves? To answer this, we examined the percentage of observerations for Aves that were observations of the Common Tern each year. We then correlated this percentage with observation year. If observations of the Common Tern are becoming more common relative to other species of Aves, the correlation should be positive, but if it is becoming less common, the correlation should be negative. In fact, the correlation is negative (r=-.45), with a negative slope (m = -.003), suggesting that the Common Tern may be in decline relative to other species of Aves. This correlation is statistically significant. (F = 30.71, p<.05)
  • The scatter chart to the right shows the percentage of all observations for Aves each year that were observations of the Common Tern.

History:

  • 1988-Lower Risk/least concern (BirdLife International 2004)
  • 1994-Lower Risk/least concern (BirdLife International 2004)
  • 2000-Lower Risk/least concern (BirdLife International 2000)

Justification

This species has a large range, with an estimated global extent of occurrence of 10,000,000 km². It has a large global population estimated to be 1,100,000¿4,500,000 individuals (Wetlands International 2002). Global population trends have not been quantified, but the species is not believed to approach the thresholds for the population decline criterion of the IUCN Red List (i.e., declining more than 30% in ten years or three generations). For these reasons, the species is evaluated as Least Concern.

Taxonomy

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  • Domain: Eukaryota Whittaker & Margulis,1978 - eukaryotes
    • Kingdom: Animalia Linnaeus, 1758 - Linnaeus, 1758 - animals
      • Subkingdom: Bilateria (Hatschek, 1888) Cavalier-Smith, 1983 - (Hatschek, 1888) Cavalier-Smith, 1983 - bilaterians

Notes:

Name Status: Accepted Name. Latest taxonomic scrutiny: 17-Oct-2001

Physical Description

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Family Laridae:

Medium to large birds, usually grey or white, often with black markings on the head or wings. They have stout, longish bills, and webbed feet.

Adult:

Head: Cap: black Bill: red, often with black tip Length: fairly short Shape: slender Neck: Nape: black Body: Rump: white Size: medium Underparts: pale gray Legs: Foot Color: red Leg Color: red Tail: white with dark outer margins Length: long Shape: forked.

Adult Breeding Season:

Head: Cap: black Color: white Crown: black in back, mixed with white nearerfront Bill: red with black tip Length: fairly short Shape: slender Neck: white Nape: black Body: Mantle: pale gray Rump: white Size: medium Underparts: pale gray Legs: Foot Color: red Leg Color: red Tail: white with dark outer margins Length: long Shape: forked.

Adult Winter:

Head: Cap: black Color: white Crown: black in back, mixed with white nearer front Bill: blackish with reddish base Length: fairly short Shape: slender Neck: white Nape: black Body: Mantle: pale gray Rump: white Size: medium Underparts: white Legs: Foot Color: red Leg Color: red Tail: white with dark outer margins Length: long Shape: forked.

Immature:

Head: Cap: black Color: white Crown: black in back, mixed with white nearer front Bill: blackish with reddish base Length: fairly short Shape: slender Neck: white Nape: black Body: Mantle: pale gray Rump: white Size: medium Underparts: white Legs: Foot Color: red Leg Color: red Wings: Secondaries: buff edgings and subterminal dusky smudges Tail: pale gray with dusky edging Length: shorter than in adult Shape: forked.

Size/Age/Growth:

About 13 to 16 inches long, with a wingspan of 30 to 31 inches. Adults weigh about 4.2 ounces.

Images:

Distribution

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Range and Population

Coastal regions worldwide, and inland waters of North America.

Diet

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Almost Exclusively: Fish Lesser Quantities of: Aquatic Invertebrates

Reproduction

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  • Breeding Habitat: Wetland-open water
  • Clutch Size: 2-4
  • Length of Incubation: 21-27 days
  • Days to Fledge: 26-27
  • Number of Broods: 1, rarely 2

Migration

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Migratory

Song/Voice

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Sterna hirundo
Recordist: Jim Stasz Copyright Holder: Jim Stasz


Courting vocalizations
Recordist: Tony Phillips Date Recorded: August 01, 1997 Location of Recording: Long Island


Courting vocalizations
Recordist: Tony Phillips Date Recorded: August 01, 1997 Location of Recording: Long Island


Courting vocalizations
Recordist: Tony Phillips Date Recorded: August 01, 1997 Location of Recording: Long Island


Courting vocalizations
Recordist: Tony Phillips Date Recorded: August 01, 1997 Location of Recording: Long Island


Courting vocalizations
Recordist: Tony Phillips Date Recorded: August 01, 1997 Location of Recording: Long Island

Similar Species

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Forster's Tern, Arctic Tern

Members of the genus Sterna:

There are approximately 166 species and subspecies in this genus. Here are just 100 of them: S. acuticauda (Black-Bellied Tern) · S. affinis · S. alb · S. alb antillarum · S. albifrons (Least Tern) · S. albifrons albifrons (Little Tern) · S. albifrons antillarum (Little Tern) · S. albifrons athalassos (Little Tern) · S. albifrons browni · S. albifrons guineae · S. albifrons praetermissa · S. albifrons saundersi · S. albifrons sinensis · S. albistriata · S. albistriata nubilosa · S. albostriata (Black-Fronted Tern) · S. aleutica (Aleutian Tern) · S. anaesthetus anaesthetus · S. anaetheta (Bridled Tern) · S. anaethetus (Bridled Tern) · S. anaethetus anaethetus · S. anaethetus antarctica · S. anaethetus fuligula · S. anaethetus melanoptera · S. anaethetus nelsoni · S. anaethetus recognita (Bridled Tern) · S. anaethetus ssp · S. anathetus · S. anglica · S. anosthaetus · S. antarctica · S. antillarum (Least Tern) · S. antillarum albifrons · S. antillarum anthalassos · S. antillarum antillarum (Least Tern) · S. antillarum athalassos (Interior Least Tern) · S. antillarum browni (California Least Tern) · S. antillarum mexicana · S. antillarum ssp · S. aurantia (River Tern) · S. balaenarum (Damara Tern) · S. bengalensis (Lesser Crested-Tern) · S. bengalensis bengalensis · S. bengalensis par · S. bengalensis torresii · S. bergii (Great Crested Tern) · S. bergii bergii · S. bergii cristata · S. bergii cristatus · S. bergii gwendolenae · S. bergii thalassina · S. bergii velox · S. bernsteini (Chinese Crested Tern) · S. beryii · S. caspia (Caspian Tern) · S. caspia caspia · S. caspia imperator · S. cautiaca · S. dougalli · S. dougalli bangsi · S. dougalli dougalli · S. dougallii (Roseate) · S. dougallii arideensis · S. dougallii bangsi · S. dougallii dougalli · S. dougallii dougallii (Roseate Tern) · S. dougallii gracilis · S. dougallii korustes · S. dougallii pacificus · S. elegans (Elegant Tern) · S. elegans (Cayenne Tern) · S. forsteri (Forster's Tern) · S. fuliginosa · S. fuscata (Sooty Tern) · S. fuscata crissalis (Sooty Tern) · S. fuscata fuscata (Sooty Tern) · S. fuscata kermadeci · S. fuscata nubilosa · S. fuscata nubirosa · S. fuscata oahuensis · S. fuscata serrata · S. fuscata ssp · S. grisea · S. hirundinacea (South American Tern) · S. hirundo (Common Tern) · S. hirundo hirundo (Common Tern) · S. hirundo longipennis · S. hirundo minussensis · S. hirundo ssp · S. hirundo tibetana · S. hybrida · S. javanica · S. lercoptera · S. leucoptera · S. longipennis · S. lorata (Peruvian Tern) · S. lunata (Gray-Backed Tern) · S. macrura · S. maxima (Royal Tern) · S. maxima albididorsalis

Bibliography

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  • Alsop, Fred J. III. Birds of North America - Eastern Region. First American Edition. Smithsonian Handbooks. DK Publishing, Inc. 2001.
  • Banks, R. C., R. W. McDiarmid, A. L. Gardner, and W. C. Starnes 2003. Checklist of Vertebrates of the United States, the U.S. Territories, and Canada.
  • BirdLife International. 2000. Threatened Birds of the World. Lynx Edicions and BirdLife International, Barcelona, Spain and Cambridge, U.K.
  • Ehrlich, P., Dobkin, D., and Wheye, D. (1988). The Birders Handbook: A Field Guide to the Natural History of North American Birds. New York: Simon and Schuster Inc. (info on clutch size, length of incubation, days to fledge and number of broods.)
  • Robbins, C.S., Bruun, B., Zim, H.S., (1966). Birds of North America. New York: Western Publishing Company, Inc. (Length and wingspan info.)

More Info

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Notes

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Contributors:

Data Sources:

Accessed through GBIF Data Portal December 06, 2007:

Identifiers:

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Last Revised: May 18, 2008