Of the approximately 9200 species of birds, only about 290

are marine species although land only covers about 29% of the

globe

Palearctic region

• Largest

• East-west mountain ranges

• Diverse in climates and habitat although much of the region is very cold

Birds of Palearctic

• 1026 species

• Birds may have evolved in this region

• Most birds are migrants and insectivorous

• One endemic family, Prunellidae

Shared species

• 12.5% with Nearctic

• 15% with Ethiopian

• 22% with Oriental

Palearctic and Nearctic form Holarctic region

• Loons, auks, grouse found only in these two regions

Nearctic region

• Also cold

• North-south mountains

Birds of Nearctic

• 740 species

• Most birds are migrants and insectivorous

• Many wood-warblers and blackbirds

• No endemic families although Meleagrididae (wild turkey) is close to being endemic

Origins of Nearctic birds

• Some are unknown—wrens, warblers, vireos, sparrows

• Some from Palearctic by way of the Bering Strait—pigeons, owls, thrushes

• Some from Neotropical region—hummingbirds, flycatchers

Neotropical region

• 70% of land surface is low elevation and with abundant moisture

• 32% of South America is tropical rain forest (only 9% of Africa, 4.5% of Australia)

• 38% of South America is savanna

Birds of Neotropical

• 3300 species• Many suboscines, as opposed to oscines• About 31 of 95 families are endemic• Some species emigrated from the Nearctic,

including pigeons, jays, blackbirds, warblers

Ethiopian region

• Less climatic variability than other regions

• Receives only half the rainfall of the Neotropical region, hence there are more deserts, grasslands, savannas

Birds of Ethiopian region

• 1556 species

• Many seed-eating and ground-dwelling birds

• Many weaverbirds, larks

• 6 endemic or nearly endemic families

Oriental region

• Smallest region

• Much of it is tropical and subtropical

• Much rain

Birds of the Oriental region

• 960 species

• Most shared species with the Ethiopian, Palearctic and Australian regions

• Two endemic families

Australian region

• Diverse climates although much of the region is dry

• Isolated region

Birds of the Australian region

• 906 species

• No woodpeckers

• Parrots and doves are important groups

• 13 endemic families

Birds may have originated in the Holarctic

• Therefore areas separated from the Holarctic by substantial barriers, e.g. Australia, sub-Saharan Africa, Madagascar, and South America tend to have more endemic taxa than areas less isolated from the Holarctic

Tropical vs. Temperate Birds

• Many more studies on temperate birds

• I will be presenting generalizations

Tropical vs. Temperate Environments

• Less seasonality due to temperature differences

• Instead, wet and dry seasons

• Many tropical food resources are available year-round

Population ecology of tropical birds

• Breeding seasons longer and more variable

• Less synchrony within a population

• Breeding seasons not always driven by food availability

• Fewer available mates in tropical systems

With fewer available mates in tropics:

Fewer EPCs

Smaller testes

Song output consistent year-round

Sexes tend to be monomorphic

Because tropical birds maintain territories year-round

• Territories are much larger than for temperate species

• Population sizes much smaller

• However, keep in mind that 1/3 of tropical birds don’t have conventional breeding territories

Other patterns:

• Nest predation higher

• Adult survival higher

• Clutch sizes lower

• More cooperative breeders

• Many species are less active

Tropical vs. temperate communities

• More species-rich

• More fruit-eaters, nectar-eaters, ant swarm followers, large insect eaters (more guilds)

• Many bigger birds in tropical areas

• More species per guild

• Mixed-species flocks year-round

• More suboscines

Tropical community characteristics

• Highest diversity within forest, not at edges

• Many intra-tropical migrants that are nectar or fruit-eaters

• Fruit and nectar-eating birds more colorful than insectivores