Friday, September 27, 2013

Curiosity Killed the Harpy Eagle!

Harpy Eagle Nestling
     An adult female Harpy Eagle (Harpia harpyja) weighs of up to 10 kg (22 lbs.) and is the largest raptor in the Americas and one of the largest in the world. They live in tropical forests from Central America to northern Argentina. This eagle is sensitive to human disturbance and is the first species to disappear when humans move into their territory. Currently, the Harpy Eagle is listed on the International Union for Conservation of Nature’s (IUCN) Red List as Near Threatened and extinct in most of the Brazilian Atlantic Forest ((IUCN) 2013). Although indigenous hunters capture them occasionally for ceremonial purposes, they are not typically hunting them as game.
Female Harpy Eagle  (photo by Raptor Canyon)
     Unfortunately, recent studies have documented Harpy Eagle killings in rural southern Brazil. (Trinca et al. 2008) conducted a study in the municipalities of Alta Floresta and Nova Bandeirantes, in northern Mato Grosso, Brazil. The Alta Floresta has suffered high deforestation leaving only 37% of original forest cover. In contrast, Nova Bandeirantes, colonised in 1981, has lost less than 15% of the municipality’s original forest due to landowners upholding federal legislation, which limits deforestation to 50% of each property. This is important because the high rate of deforestation is the main reason for the declining population of Harpy Eagles ((IUCN) 2013).
     The results of the (Trinca et al. 2008) study are quite disturbing. In addition to the Harpy Eagle killings several other important raptor species are being killed such as Crested Eagles (Morphnus guianensis) and Ornate Hawk-Eagles (Spizaetus ornatus). Five of the eagles kill were to satisfy the curiosity of the hunter. One explanation is that most colonos are immigrants from rural south and east of Brazil, where Harpy Eagles are either extremely rare or extinct, have never seen this eagle. The other reason, for killing the eagle, was to protect small livestock from the perceived or actual risk of having an eagle in the area. The presence of a Harpy Eagle near human activity may be a result of lower prey due to the deforestation and habitat fragmentation.

     The number of eagles killed may appear small but they impact the local Harpy Eagle population because a single breeding pair may possess a home range of over 25× 25 km. In addition, Harpy Eagles are long living predators and reproduce only one nestling every two years. As an apex predator, Harpy Eagles play an important role in the forest ecosystems by regulating the populations of mesopredators such as capuchins (Cebus spp.) a type of New World monkey. The absence of such apex predators will have a negative impact on biodiversity that contributes to cascade effects as well as accelerating local extinctions of sensitive species. Therefore, the removal of such arbitrary hunting pressure would undoubtedly contribute significantly to long-term conservation. This statement sums up the problem and solution for all raptors sharing the Earth with humans:

If ignorance is the main enemy of the Harpy Eagle on the Amazonian frontier, education is surely its principal ally, and the same characteristics that attract the attention of the curious hunter, can undoubtedly be part of a well-planned education program to not only satisfy the local population’s curiosity and eliminate misconceptions about the species, but to provide a springboard for conservation initiatives in frontier municipalities (Trinca et al. 2008).

 Remember as you live your life, it may affect a species of raptor that shares its habitat with you. 

 To learn more about the eagles:
Literature Cited

Sunday, September 22, 2013

An Owl with an Image Problem!

     In Africa, the owl is an omen. Many African cultures believe that if a person sees an owl, someone they know will die or something bad will happen in the village. This is a problem for the owl because villagers will kill owls or scare them away causing them to lose their home, food or nest. So, how do we solve this problem? Some scientists are looking for the answers.
      In Kenya, scientists studied how local farmers viewed owls, specifically the Mackinder’s Eagle Owl (Bubo capensis). They asked the farmers (72 interviewed) if they believed owls were a negative sign, such as a death or tragedy. Then the scientists asked if they had negative, no feelings or positive feelings towards owls. Almost half the farmers (44%) had no feelings toward owls but 30% felt negatively. Only fifteen farmers had positive feelings about owls. What was different about the fifteen farmers that thought positively about owls? Simply, the answer was money.
     Owls provide a very important service (ecoservice) for the farmers; they provide pest control! All farmers interviewed expressed pest problems on their farms. Small mammals such as rats and mice eat their crops. Obviously, this causes the farmer to lose money. Over half the farmers did nothing to control the pests but the others used chemicals to kill insects or rats and mice. Even some farmers used poison to kill pests by using large amounts of these chemicals. This action not only kills the pests, it kills the animals that eat them.
     The scientists determined that farmers that felt positively about owls also understood that they were good for eating farm pests. The farmers that had no feeling or negative feelings did not think of owls as pest control. The solution seems to be to educate the farmers on the free ecoservice of pest control that owls provide. This free ecoservice is not just provided by owls in Africa but all raptors all over the Earth. Please remember when you use poison, you are not just poisoning the intended but raptors as well!

To learn more about owls try these websites:

Literature Cited

Ogada, D. L., and P. M. Kibuthu. 2008. Conserving Mackinder's eagle owls in farmlands of Kenya: assessing the influence of pesticide use, tourism and local knowledge of owl habits in protecting a culturally loathed species. Environmental Conservation 35:252–260.  

Wednesday, September 18, 2013

North America’s Best Kept Secret

     If you live in North America, chances are you have heard of the Bald Eagle (Haliaeetus leucocephalus), Peregrine Falcon (Falco peregrinus) or Red-tailed hawk (Buteo jamaicensis) but what about the Ferruginous Hawk (Buteo regalis)? The Ferruginous Hawk is North America’s largest hawk (Buteo) species and considered a specialist, which means this hawk is fussy eater. In addition, their menu is limited to rabbits (Lepus spp.), ground squirrels (Spermophilus spp.) and prairie dogs (Cynomys sp.) but when desperate for food, it will eat small mammals as well as dead animals. It only lives in open grasslands, shrub steppes and deserts of western North America and avoids forests and farms. They like to nest in trees surrounded by open prairie and grazed landscape but they will nest in cliffs and on the ground. The northern population of Ferruginous Hawks is migratory, nesting in the northwestern states and Canada and wintering in the southwest and northern Mexico. The southern population does not migrate. Wyoming has the largest population of year-round residents.

     There is evidence from various studies that Ferruginous Hawks are declining ( Schmutz and Fyfe 1987, Woffinden and Murphy 1989, Schmutz et al. 2008). Currently, the United States Bureau of Land Management lists the Ferruginous Hawk as sensitive as well as a species of concern or endangered in several states. In Canada, the Committee on the Status of Endangered Wildlife listed them as threatened in 1980, vulnerable in 1995 and threatened again in 2008. In addition, because of a persistent trend of decline in Alberta, the Providence lists the Ferruginous Hawks as endangered. What is the problem? Well, it is complicated. In addition to being finicky on where they live and what they eat, they do not tolerate people. This makes it difficult for scientists to study them and for the public to get to know them.
     What do scientists know about them? Human disturbance during nesting causes the birds to abandon their nest and/or nestlings. However, they are not as affected by human interaction during the non-nesting season. Depending on where the Ferruginous Hawks live, jacket rabbits and ground squirrel are important to their reproduction. Studies have revealed they will halt reproduction if rabbits and ground squirrels are not plentiful. 

     Lack of menu choices for this fussy hawk might be the reason they are declining. A few scientists believe there is a decrease in jacket rabbits in the West. In the East, ground squirrels and prairie dogs are considered farm pests and are poisoned. In addition, they are losing habitat to farmland. The best way to make prairie dogs leave your farmland is to invite a pair of Ferruginous Hawks to nest on your property!
Sadly, most Ferruginous Hawks do not survive their first birthdays due to starvation or human impacts such as gunshot, poisoning, hit by cars or electrocution from perching on power poles. The increase in wind farm construction impact this hawk as well as all raptors. Raptors fly into the turbines or are disturbed by the increase in human activity during construction. Often the same windy areas that are great for wind farms are also used by migrating raptors.

Good news! Raptor conservationists are working hard to help the Ferruginous Hawk. 

Literature Cited

SCHMUTZ, J.K., D.T.T. FLOCKHART, C.S. HOUSTON, AND P.D. MCLOUGHLIN. 2008. Demography of Ferruginous Hawks Breeding in Western Canada. Journal of Wildlife Management 72:1352-1360.  

------------- AND R.W. FYFE. 1987. Migration and Mortality of Alberta Ferruginous Hawks. The Condor 89:169-174.  

WOFFINDEN, N.D., AND J.R. MURPHY. 1989. Decline of a Ferruginous Hawk Population: A 20-Year Summary. The Journal of Wildlife Management 53:1127-1132.

Silent Killer

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