How
Long Can Birds Live?
Precise
information on the longevity of birds is not easy to come
by. It is usually impossible to follow large groups of
individuals from hatching to death, so in addition to
collecting data directly by banding and recapturing
individuals, many indirect methods of estimating age are
used. Generally, it appears that the heaviest post-fledging
mortality occurs among inexperienced young birds, and that
for adults, after they have successfully reared young, the
probability of death each year remains roughly constant. In
other words, few birds die of "old age -- they just run the
same gamut of risks year in and year out until they are
killed. The annual risk of being killed varies from about 70
percent in small temperate-zone songbirds (adult life
expectancy about 10 months; in the tropics adult songbirds
are thought to be much longer-lived) to 3 percent in Royal
Albatrosses (fife expectancy slightly over 30 years). If a
bird lasts long enough, however, the probability of it dying
in a given year may once again rise. Common Terns reach old
age after about 19 years, and their annual risk of dying
then goes up.
Life expectancy in birds is
closely correlated with size -- the larger the species, the
longer it is likely to live. But the relationship is far
from exact. Some groups of birds tend to have long lives for
their sizes, especially the Procellariiformes (tubenoses --
albatrosses, shearwaters, and petrels) and Charadriiformes
(shorebirds, gulls and terns, and auks). Other groups, for
instance titmice and chickadees, wrens, and game birds, are
shorter-lived than their sizes would predict.
Birds can be very long-lived
in captivity. One Sulphur-crested Cockatoo (a common
Australian parrot made famous by the TV show "Baretta")
lived most of his 80-plus years in a zoo. Captive Canada
Geese have lived for 33 years, House Sparrows 23 years, and
Northern Cardinals 22 years. In nature, the life-spans of
these species are much shorter. As luck would have it,
however, the record for a European Starling in the wild, 20
years, is 3 years longer than for any starling
captives.
The table on the next page
gives longevity records (years-months) of wild birds. Small
differences among these figures should not be taken too
seriously. For one thing, they represent the upper end of a
range -- and the range of any measurement is a statistic
that almost always increases with the number of
measurements. If, for instance, you record the heights of a
random sample of 10 American women, and then of another
sample of a million American women, both the tallest and the
shortest woman are virtually certain to be in the larger
sample. So the minimum life-spans of bird species that are
frequently banded are more likely to be greater than those
of species rarely banded, everything else being equal. It
seems likely, for example, that the short record for the
Northern Shrike is simply a result of a low frequency of
banding. At any rate, remember that with the exception of
efforts that may later be corrected, the numbers on the list
can only increase. Remember also that these figures are
maximum recorded ages. While at one point the maximum record
for the Purple Finch was 10 years (it has since been
extended to almost 12), of 1,746 recoveries from 21,715
banded individuals, only I lived 10 years, 6 lived 8 years,
and 18 lived 7 years. All the remainder lived less than 7
years. In short, the maximum life-span is far longer than
the median life-span (the length of the life of the
individual that lives longer than half the population and
shorter than the other half), which in songbirds is usually
only a year or two.
Maximum Recorded
Lifespans
SPECIES
|
YR.-MO
|
SPECIES
|
YR.-MO.
|
Laysan
Albatross
|
37-05
|
White-crowned
Sparrow
|
13-04
|
Arctic
Tern
|
34-00
|
House
Sparrow
|
13-04
|
Great
Frigatebird
|
30-00
|
Warbling
Vireo
|
13-01
|
Western
Gull
|
27-10
|
Brown
Thrasher
|
12-10
|
Common
Murre
|
26-05
|
Black-bellied
Plover
|
12-08
|
Trumpeter
Swan
|
23-10
|
Wrentit
|
12-07
|
Great
Blue Heron
|
23-03
|
Wild
Turkey
|
12-06
|
Canada
Goose
|
23-06
|
Black-capped
Chickadee
|
12-05
|
Mallard
|
23-05
|
Peregrine
Falcon
|
12-03
|
American
Coot
|
22-04
|
Sanderling
|
12-01
|
Osprey
|
21-11
|
American
Kestrel
|
11-07
|
Bald
Eagle
|
21-11
|
Song
Sparrow
|
11-04
|
Red-tailed
Hawk
|
21-06
|
Black-and-white
Warbler
|
11-03
|
Brown
Pelican
|
19-08
|
Tree
Swallow
|
11-00
|
Mourning
Dove
|
19-03
|
Broad-tailed
Hummingbird
|
11-00
|
Sandhill
Crane
|
18-06
|
Acadian
Flycatcher
|
10-11
|
Great
Homed Owl
|
17-04
|
Killdeer
|
10-11
|
Northern
Harrier
|
16-05
|
Dark-eyed
Junco
|
10-09
|
Blue
Jay
|
16-04
|
Scarlet
Tanager
|
10-01
|
Hairy
Woodpecker
|
15-10
|
Cassin's
Auklet
|
9-01
|
Brown-headed
Cowbird
|
15-10
|
Ruby-throated
Hummingbird
|
9-00
|
Northern
Cardinal
|
15-09
|
House
Wren
|
7-01
|
Red-winged
Blackbird
|
15-09
|
Golden-crowned
Kinglet
|
5-04
|
American
Crow
|
14-07
|
Allen's
Hummingbird
|
3-11
|
Great
Crested Flycatcher
|
13-11
|
Northern
Shrike
|
3-03
|
American
Robin
|
13-11
|
Blackpoll
Warbler
|
3-05
|
Lesser
Prairie-Chicken
|
13-06
|
|
|
Recent work on seabirds by
ornithologist Ralph Schreiber of the Los Angeles County
Museum indicates that dramatic increases in longevity
records of seabirds can be expected as more data are
gathered. For example, there are now thousands of banded
Laysan Albatrosses that are in their 30s. It is likely that
these and some others will eventually be shown to have
life-spans of 50-70 years, longer than those of the rings
used to band them!
The records presented in our
list are from Dr. M. Kathleen Klimkiewicz of the Bird
Banding Laboratory of the U.S. Fish and Wildlife Service
(with the exception of the Broad-tailed Hummingbird, which
is courtesy of Dr. William Calder). They are updated to
September 1, 1986. Records for all North American species
may be found in three papers by Dr. Klimkiewicz and her
colleagues published (and one soon to be published) in the
Journal of Field Ornithology. Updates of the records in the
earlier papers will appear in the same journal.
SEE: Population
Dynamics.
Copyright
® 1988 by Paul R. Ehrlich, David S. Dobkin, and Darryl
Wheye.
|