OrnithologyThird Edition

Chapter 21Conservation

Copyright © 2007 by W. H. Freeman and Company

Frank B. Gill

and Mr. Baker

Part 4 – Conservation by Design

Conservation Biology sets priorities and integrates objectives with large-scale plans of habitat management.  The goal is to protect and restore habitat in an effort to maintain healthy ecosystems with broad spectra of plants and animals.

The design of nature reserves must take into account bird movement and their seasonal needs.  Corridors allow movement between reserves, which helps maintain genetic diversity.  Designs and locations must be able to adapt to changes in climate - such as those due to global warming.

Populations of plants and animals tend to occur in patches - local populations.  Local populations that interbreed are grouped into "metapopulations“.

If a local population disappears, other members of the metapopulation may move in and restore it.  Managing populations must take two factors into account:

1.The probability of extinction of populations.

2.The importance of maintaining genetic diversity.

Population viability model for the Florida Scrub Jay. Computer simulations show that the probability of short-term extinction of an isolated set of territories decreases with the size of the starting population (see numbers). Populations with only a single family group territory are likely to disappear within 50 years, but populations with 100 territories will last for centuries.

Small, fragmented populations lose genetic diversity (due to inbreeding or chance). This reduces survival and fertility, such that the population may not be able to recover.

Greater Prairie Chicken populations in Illinois dropped to the extent that conservation biologists imported birds from larger, more diverse western populations to maintain the genetic diversity.

Populations trends and fertility in a remnant population of Greater Prairie Chickens in southeastern Illinois. Counts of breeding males (bottom line) declined steadily after a brief peak in 1972, until extra males were introduced from other, larger populations. Genetic diversity and egg-hatching rates (top line) declined in this small population, but then rebounded after birds from other populations were introduced in 1990.

Human activities such as cutting forests or converting grassland to cropland divide areas of habitat into smaller fragments.  Small size and extensive edges of fragments leads to...

• increased predation• limited space for foraging and other activities• invasion by exotic species• reduced nest success• reduced survival of adults

Forest fragmentation in Missouri – nonforested (left) and forested (right) landscapes.

Dark areas are forested.

Forest fragmentation in N.Am. leads to higher rates of brood parasitism (laying eggs in someone else's nest to reduce your cost of reproducing and raising young) by Brown-Headed Cowbirds.  Cowbird eggs tend to hatch sooner than the eggs of the host bird, and the cowbird chicks will push other eggs and chicks out of the nest.

INBU – Indigo Bunting WEWA – Worm-Eating WarblerOVEN – Ovenbird KEWA – Kentucky Warbler

Parasitism is highest within 100-200m of the forest edge.  The interior is relatively safe, so larger chunks of habitat are safer than smaller ones. Small fragments tend to be population sinks - places where local populations die out quickly.

Songbird nesting success increases with distance (10 categories from 0 to 123m) from the forest edge, where nest parasitism (by Brown-Headed Cowbirds) is greatest.

Minimum critical size studies in the Amazon rainforest showed the following...• Local landscapes should include some forests larger than 1000 hectares.  These larger fragments can supply birds to smaller fragments to ensure genetic diversity.• Corridors allow birds to travel from fragment to fragment, aiding diversity.  They also allow young birds to disperse.  Forest corridors only need to be 100-300m wide to be effective.

Natural disturbances, such as floods and fires, are a key part to keeping habitats vital.  Healthy ecosystems include a variety of habitats, in different stages of recovery.  Without this, there would be less habitat diversity, supporting less bird diversity.

Before the colonization of N.Am., one-half of the continental U.S. burned every 1-12 years due to fires started accidentally by lightning or deliberately by Native Americans.  Many habitats require regular burning in order to maintain themselves.  This is especially true of grasslands - fire favors the growth of grasses, while discouraging the woody plants that would naturally take over due to succession.  Young grasslands provide thick groundcover for nesting and a greater diversity of insect prey.

Regular (in many cases, seasonal) flooding...

• creates backwater lakes and habitats• replenishes vital nutrients• resets plant succession on new soils

Floodplain habitats are threatened by dams, channels, levees and other human attempts to control/minimize flooding.

Florida Scrub Jays live only in the scrub habitats of central Florida.  These habitats are renewed by regular fires (ever 8-15 years).  When fires were suppressed by humans, the Scrub Jay populations declined due to competition from Blue Jays and predation by hawks and snakes.  When the habitats were burned, Scrub Jay populations rebounded for a while, then began to decline - in anticipation of the next burn.

Grasslands were originally grazed on by bison, antelope, and elk.  More recently, they are grazed by domestic livestock.  Overgrazing creates deserts, but moderate grazing and the rotation of livestock can help maintain healthy grassland.  Birds such as Horned Larks and Montezuma Quail benefit.

In the US, commercial harvesting of trees for lumber causes more disturbance of habitat than natural processes do.  As an area is cut, it then begins a series of successional stages in the process of recovery.  Each stage accommodates a different set of species with specific habitat preferences.  As the area matures, the species present change.

As this area grows in, it will be colonized first by Winter Wrens, Eastern Bluebirds, and Northern Flickers.

Within two to three years, species such as Mourning Warblers, Common Yellowthroats, and Swainson’s Thrushes will move in.

About half of Neotropical migrants that breed in hardwood forests prefer early stages of succession.

The shifting forest mosaic model. Forestry cutting of trees creates a variety of successional stages in the landscape. Different shades denote four stages of forest age from young to old. The stages “move around” over time as the forest grows and is cut in different years. Ideally, a full complement of plant and animal species will colonize each stage.

Spotted Owls rely on old growth forests of the Pacific Northwest.  As these areas have been logged, the Spotted Owl habitat has declined.  Fragmentation allows more competition from larger Barred Owls, and more predation by Great Horned Owls.  Programs to protect habitat for Spotted Owls have been put in place.

To focus their resources on areas of greatest need, conservation biologists have identified "hot spots" - places in the world that are under threat and have the highest amounts of biodiversity.  There are three main factors that define a "hot spot"...• Largest number of total species.• Highest number of threatened/endangered species.• Most endemic species (not found anywhere else on Earth).

Identified hot spots include...

• the tropical Andes of South America

• the Amazon River Basin (S. Am.)

• Atlantic Coastal Forest of S. Am.

• Guyana Highlands (S. Am.)

• the Himalayas

• the Rift Valley of Africa

More recently, the Important Bird Areas (IBA) program was established to protect a world-wide network of sites that stabilize bird populations and their essential ecosystems. 

The IBA network includes federal wildlife refuges and other protected public lands, as well as private and local community lands. 

So far, about 3,000 sites have been identified in the Western Hemisphere - with plans to grow to about 8,000 sites.

Thus far, there are 15 IBAs in NH. There is a link to their website on the eBoard!

Community support is vital to the success of any conservation movement.  Thus, programs must take into account economic and social variables, as well as biological ones. Local pride is often the key to public support.  An endangered parrot, the Jacquot, was saved when conservation programs rallied the people of the island of St. Lucia.  The Jacquot is now the island's national bird and its population has nearly doubled.

The Conservation MovementThe excesses of the 1700's and 1800's led to the beginnings of the conservation movement in the late 1800's.  The American Ornithologists Union was founded in 1883, followed by state Audubon Societies and federal agencies such as the U.S. Bureau of Biological Survey. The movement was supported by the writings of famous authors of the time, such as Ralph Waldo Emerson, Walt Whitman, John Burroughs, and John Muir.

Emerson Whitman Burroughs Muir

1887 - Fannie Hardy and Florence Merriam founded the first Audubon Society at Smith College in Massachusetts.  The goal was to get people on campus to stop wearing bird feathers. 1896 - Harriet Hemenway founded the Massachusetts Audubon Society.  The goal was to discourage ornamental use of wild bird feathers and to protect birds. 1934 - Rosalie Edge purchased 1400 acres on Hawk Mountain in PA, and hired a warden (Maurice Broun) to protect the hawks passing through this key part of their migration route.  The goal was to protect hawks and gain public support by encouraging hawk watching.  Hawk Mountain now maintains the world's longest and most detailed record of raptor migration.  The millionth raptor was logged on October 8, 1992.  This database was used to uncover the connection between DDT and raptor mortality rates.  It was also used to track population recovery when DDT was outlawed.

The lookout at Hawk Mountain near Reading, Pennsylvania.

Several environmental crises launched the modern environmental movement and motivated Congress to pass key environmental laws.

•1964 - The Wilderness Act

•1969 - The National Environmental Policy Act & the Environmental Protection Agency

•1970 - The Clean Air Act

•1972 - The Clean Water Act

•1973 - The Endangered Species Act

•1974 - The Safe Drinking Water Act

President Nixon's administration (1969-1974) accomplished more significant environmental legislation than any before or since - with the possible exception of Theodore Roosevelt (1901-1909).

Various local and national nonprofit organizations grew to engage the public.  Today, there are more than 1,000 independent bird clubs, bird observatories, coalitions, and Audubon chapters in North America.  Birdlife International is a coalition of national bird conservation organizations worldwide.In 1986, the US, Canada, and Mexico developed the North American Waterfowl  Management Plan (NAWMP).  The goal was to protect millions of acres of wetlands and meet population goals for 32 species of ducks, geese, and swans. In the 1990's, two more organizations arose...• Partners in Flight (PIF) was a coalition of government and nongovernment agencies, corporate leaders, and academic professionals.  The goal was to protect populations of Neotropical migrants.• The North American Bird Conservation Initiative (NABCI) expanded the work of PIF to include "all birds, all habitats".

Citizen science is research done by people from every level of society in collaboration with scientists.  The oldest example of citizen science in the world is the Christmas Bird Count, which was started by Frank Chapman in 1900, in which volunteers from around the US and Canada report on how many birds/species they observe over the Christmas holidays.

Chapman

There are an estimated 46 million birders (age 16 and up) in the US.  On average, they are well educated, earn above-average incomes, and belong to several conservation organizations.  They range from beginners who can identify only a few species to experts who keep life lists of species seen.

A "birder" is defined as someone who "closely observed or tried to identify birds around the home and/or took a trip a mile or more from home for the primary purpose of observing birds." 

Birding provides economic support for communities and governments, as well. 

In 2001, US birders and wildlife watchers spent an estimated $24 billion on binoculars, bird food, camp equipment and other items; and another $7 billion on travel. 

This generated about $85 billion in economic output and $13 billion in state and federal income taxes.

Birding Ethics by the American Birding AssociationEveryone who enjoys birds and birding must always respect wildlife, its environment, and the rights of others. In any conflict of interest between birds and birders, the welfare of the birds and their environment comes first.1. Promote the welfare of birds

and their environment.• Avoid stressing birds or

exposing them to danger: exercise restraint and caution during observation, photography, or recording/filming.

• Limit the use of recordings and other methods of attracting birds. Never use such methods in heavily birded areas or for attracting any threatened or endangered species.

2. Respect the law and the rights of others.• Do not enter private

property without the owner’s permission.

• Follow all laws, rules, and regulations governing the use of roads and public areas.

3. Ensure that feeders, nest structures, and other artificial bird environments are safe.• Keep dispensers, water and

food clean. It is important to feed birds continually during harsh weather.

• Maintain and clean nest boxes regularly.

• If you are attracting birds to an area, ensure that they are not exposed to predation from cats or other domestic animals or to dangers posed by artificial hazards.

4. Group birding, whether organized or impromptu, requires special care.• Continued…

Birding Ethics by the American Birding AssociationEveryone who enjoys birds and birding must always respect wildlife, its environment, and the rights of others. In any conflict of interest between birds and birders, the welfare of the birds and their environment comes first.

4. Group birding, whether organized or impromptu, requires special care.• Respect the interests,

rights, and skills of fellow birders, as well as those of people participating in other legitimate outdoor activities.

• Freely share your knowledge and experiences. Be especially helpful to beginning birders.

• If you witness unethical birding behavior, assess the situation and intervene if you think it prudent.

Please follow this code – distribute it and teach it to others.

In 1953, American naturalist Roger Tory Peterson and British ornithologist James Fisher journeyed across North America and surveyed the bird species that lived there.

They documented their journey in the book Wild America (1955). Fisher concluded the book with the following quote…

“Never have I seen such wonders, or met landlords so worthy of their land. They have had, and still have, the power to ravage it; and instead they have made it a garden.” [Fisher, pg. 418 in Wild America]

Fifty years later, author/naturalist Scott Weidensaul took another look at North America and made the comment…

“I found the continent changed – for the better in some places, for the worse in others. Yet the land, the rugged heart of natural America, retains an essential timelessness... Ours is still, at its core, a wild country.” [Widensaul 2005, pg. xx]Chapter 21 – the last chapter in your Ornithology

book – ends with this paragraph…

“Our knowledge of birds and our appreciation of them can assure their future and ‘the rugged heart of the planet.’ That has been the theme of this book. Each of us can make a difference. Please start now.” [Gill 2007, pg. 684]

End of Part 4.