Credit: Reprinted with permission from Wiley-Blackwell
A Climate Change Winner
A study in the International Journal of Avian Science (v. 152/1) indicates
that common eiders (Somateria mollissima) in Iceland could benefit from a
warming climate. Drawing upon a 30-year dataset of a population of farmed
eiders, researchers from the University of Glasgow led by Liliana D’Alba
compared records of temperature (which generally warmed over the period)
to eiders’ reproduction and survival. The analysis showed that, over the 30
years, eiders shifted their egg-laying one week earlier and the population as a
whole quadrupled. Population increases were tied to warmer breeding season
temperatures two years prior, when the newest breeding females in the population hatched. Earlier laying dates may stem from greater food availability,
and the larger population size could result from increased survival, less nest
abandonment due to bad weather, and farmers’ efforts to keep away predators
and attract birds. Yet the direct correlation between weather and yearly variations in numbers, the authors say, indicates that climate has influenced this
eider population, which may grow further as the climate warms.
Credit: Reprinted with
permission from elsevier
Keeping Predators Out
In an effort to protect ground-nesting
birds like the piping plover (Charadrius
melodus) from the threat of predation,
conservationists have built fences around,
and in some cases on top of, entire nesting areas. But little research had been
done to confirm that these structures
(or exclosures)—which were sometimes
electrified to deter predators, thus posing
an electrification risk to the birds themselves—actually did more good than harm.
To see if this common practice yielded a
net positive for nesting success, Rutgers
University graduate student Brooke Maslo
and associate professor Julie Lockwood
analyzed 10 years of piping plover nesting
data from New Jersey, sharing their findings in Biological Conservation (v.142/12).
They found that exclosures indeed boosted
hatching success: Birds in protected nesting areas were three times more likely
to hatch at least one young than birds in
unprotected areas. However, electrified
exclosures correlated with lower rates of
hatching and higher rates of nest abandonment than unelectrified exclosures. Maslo
and Lockwood note that the presence of
both predators and humans led to higher
rates of nest abandonment, and suggest
that more research into those influences
is necessary. In the meantime, they recommend that those interested in protecting
shorebirds like plovers stop using electrified exclosures.
Credit: Southwest association
of naturalists
Burrows Do Double Duty
It’s rough living in the extreme environment of the Mojave Desert, where summer
temperatures can reach well above 100
degrees Fahrenheit, winter temperatures
may fall into the single digits, and only
five inches of rain fall each year. At least
one bird species has found an interesting
way of coping, researchers report in The
Southwestern Naturalist (v. 54/4). A team
led by Andrew Walde of ITS Corporation
observed the ground-dwelling horned lark
(Eremophila alpestris) making use of desert tortoise (Gopherus agassizii) burrows
on four separate occasions—including
instances where adult birds stood in a
burrow or fledglings stayed in the burrow
while an adult periodically stopped in to
feed them. The researchers recorded air,
ground, and burrow temperature and humidity on each of these occasions, finding
that the burrows could be up to 45 degrees
Fahrenheit cooler and much more humid
than the exposed ground at mid-day in
summer. These burrow microclimates, the
authors suggest, allow the larks to avoid
water loss, stress, and even death in the
Mojave. Given the changing climate and
declines in desert tortoise populations, the
researchers recommend further research
to find additional species that may depend
on these burrow sanctuaries.
