FW 311 New Stuff for Final

Neotropical

1. 30% of world total 2. 31 endemic families 3. Dominant families are Trochilidae, Tyrannical, Furnariidae, Formicariidae 4. Most unique and diverse avian fauna in world 5. Many frugivores, nectarivores, aerial insectivores 6. Few seedeaters and carnivores 7. Fauna dominated by group called suboscines, rather than oscines - South America, Central America, lowlands of Mexico, West Indies - Several factors contribute to the maximum diversity, but the overriding explanation is that this is the largest contiguous land mass located at tropical latitiudes

Nearctic

1. Few/simple habitats 2. Dominant families are Emberizidae and Parulidae - example: wood warblers 3. No endemic families 4. Few frugivores, nectarivores, or ground insectivores 5. Many migratory species - This regions includes parts of Mexico, U.S., Canada, and Greenland - Arctic tundra, boreal forest, temperate forest, grassland, desert

Bird communities are the result of processes happening at 2 different time frames

1. Historical 2. Ecological - Both sets (long and short term) of patterns help shape the communities we see today

Oceania

1. Huge global area 2. Very few habitats 3. Dominant group is Procellariiformes - albatross, shearwaters,petrels Refers to the open ocean islands away from continental shelves - Ocean currents play a major role in determining regional productivity... upwelling - Dynamic soaring allows these birds to forage the widely separated food sources - Morphological patterns among albatrosses is for the largest species to be found at latitudes with the strongest prevailing winds... they require faster speeds to stay aloft due to their size

Given longer breeding seasons and no severe winters to endure, why should tropical birds lay so few eggs?

1. Lack's Hypothesis - individuals produce as many offspring as they can, with the constraint that those offspring have to be healthy enough to survive so they can reproduce the next generation ...True fitness is measured by how many grandkids you leave - focused on the idea that since SEASONALITY is reduced so is the amount of food that parents can provide to their kids (the parents only have 12 hours to forage in day light rather than the extended 18 hours in more temperate latitudes) 2. Ashmole's hypothesis - extension of Lack's ideas - further suggested that SURVIVAL RATES OF ADULTS played a very important role as well - Yes, seasonality is less in the tropics and this leads to less annual fluctuation in food availability. But, if seasonality is lower, meaning no sever winter, this would lead to higher annual adult survivorship - which could mean that populations would not fluctuate widely, leaving little room in the environment for recruitment of new offspring. - make large, healthy babies that can better fight for limited resources 3. Sketch's hypothesis - disagreed with Lack -food is not limiting in the tropics as seen in how tropical insectivores often catch and eat very large insects and how so much fruit from trees falls to the ground before birds can eat it - agreed with Lack and Ashmole in that seasonality and its influence on ADULT SURVIVAL may play roles - state that high risk of PREDATION limited clutch size and that since most eggs and nestlings will be eaten by predators which means the parents must attempt more often and must save their energy for these multiple attempts - also, by cutting down on the time spent at the nest they cut down on the risk of predation

Afrotropical

1. Large Area, diverse habitats 2. Six endemic families 3. Dominant families are Ploceidae and Laniidae 4. Many cursorial species, seedeaters

Palearctic

1. Largest area, but species/area ratio low 2. Many migratory species in common with Neurotic, Indomalayan, and Africotropical 3. 69 families, 1 endemic 4. Dominant group Sylviidae (old world warblers) 5. Dominant ecological types are ground and foliage insectivores 6. Few nectarivores or frugivores - Includes all Europe, almost all of Asia, and North Africa - Might be were birds first evolved

Australasian

1. Low species diversity - 70% desert 2. 64 families (13 endemic) 3. Dominant families are Psittacidae and Columbia 4. Many frugivores, nectarivores, kingfishers 5. Few ground insectivores and foliage gleaning insectivores - Regions includes Australia, New Zealand, Papua New Guinea, and other islands in the area - The region is generally dry (4% rain forest 70% desert) and the desert only supports 3% of the regions avifauna - Secluded by desert, it has many endemic populations

Can we extend the thinking presented by the Tropical Life History Syndrome to other situations?

1. Oceanic islands vs. Interior islands - Oceanic will have more severe weather and possibly less food, but less predation and high seasonality - I would assume higher clutch size 2. Low elevations vs. High elevations - High elevations would also have more extremes but less predation - I would predict high elevations having higher clutch size

Indomalayan

1. One endemic family - Irenidae (leaf birds) 2. No major lifestyles missing 3. Dominant families are Phasionidae and Columbia 4. High species diversity per unit area - The line between Australasian and Indomalayan realms reflects a significant shift I species associations and follows a deep trench in the ocean floor that likely maintained physical isolation between landmasses during glaciation

Barriers

1. Physical: the line dividing Indomalayan from the Palearctic follows the Himalayan Mountains. Lowland birds from either side are prevented from mixing because the inability to disperse over the mountains. - other examples include oceans or deserts 2. Ecological: all those species in the Neotropics that specialize on flowering plants drop out as the plants they depend on vanish at temperate latitudes 3. Psychological: Some land birds are reluctant to cross even relatively small bodies of water. Tropical birds adapted to the understory don't even cross medium size rivers. Thus, lowland forest birds on Lombok might be able to see Bali, but they don't want to go there.

Key life history traits

1. Rate of development 2. Age at first breeding 3. Number of eggs/nesting attempt is clutch size 4.number of nesting attempts per year 5. lifespan

Why do the Neotropics have so many species?

1. Refuge Hypothesis - Historically, the most accepted explanation - states that repeated fragmentation of tropical forest habitats caused by climate change associated with glacial cycles provided conditions for multiple speciation events - this same process has been proposed as a mechanism for speciation in North America 2. Increased Niche Availability - Ecologically, the diversity stems from a greater variation in foods, variation in habitat types, and the stable climate a. greater variety of food types to exploit b. greater range of prey sizes within a food type c. stable climate promotes specialization (predictability allows for more specific evolution d. greater structural habitat diversity (restricted access to different canopy levels - All these create many available niches e. large altitudinal range at tropical latitudes - Just as the tropical forest creates vertical stratification, the large altitudinal range of the Andes creates great diversity f. the tropics experience a seasonal influx of migrants from Nearctic - looking at relative size of breeding vs. wintering area, we see that wintering species from throughout N. America get funneled into a much smaller geographic area in Central and South America NET RESULT: avian diversity reaches its peak in western S. America

How does speciation occur?

1. The ALLOPATRIC speciation process begins with a contiguous population of species 'A'. This continuity refers to genetic continuity (although we always show it as geographic continuity in this basic model), it is possible for populations to be separated in space but connected genetically via dispersal, immigration and emigration. 2. Something occurs that separates this single population into two separate (i.e., allopatric) populations of species A (A' and A") that are genetically and geographically isolated from each other (the barrier [yellow line] effectively prohibits exchange of individuals). Separation might result from a variety of geological or ecological processes including: i. Climate: glaciers, flooding, drought ii. Mountain range uplift iii. Rare colonization event of discontinuous habitats (e.g., oceanic islands) iv. Continental drift 3. In ALLOPATRY i. natural selection causes A' and A" to evolve to match their local conditions ii. during this process A' and A" develop traits that effectively result in reproductive incompatability (isolation). Possible reproductive isolating mechanisms include: a. courtship behavior b. anatomical c. characters that signal species identity d. factors that influence viability of offspring that prevent individuals from each population from successfully interbreeding (they have become species B and C) 4. At some later time, the barrier separating these two new species evaporates - 2 species expand towards each other and eventually their distributions overlap (called SECONDARY CONTACT)

What factors conspire to favor the evolution of such a diversity in developmental patterns?

1. Tradeoffs - effort directed at one thing necessarily reduces the effort available for something else - example: optimal clutch size

What are the differences between developmental categories?

1. Wholly independent at birth - moundbuilders - black-headed duck 2. Precocial - hatchlings leave the nest immediately and follow their parents. - chicks feed themselves, but parents may help find food - parents will brood offspring when young - ducks - shorebirds - quail - grouse 3. Subprecocial - hatchlings leave the nest immediately, but are fed directly by their parents - rails - cranes - coots - grebes & loons (in which parental care extends to giving them a ride on their back to keep warm) 4. Semiprecocial - hatchlings capable of body temperature regulation (like earlier categories) and are mobile around the nest, but generally stay in the nest for some period of time and are fed by parents - gulls - terns - petrel - penguins 5. Hatchlings stay in the nest, but are mobile, fed and brooded by parents - herons 6. Altricial - hatchlings naked, blind, and helpless at hatch - songbirds - hummingbirds - pigeons - parrots

Brood Reduction

An adaptation of some birds to keep a consistent clutch size year to year even though food availability may vary by creating competitive asymmetry among brood mates in the nest. Two most common: - Variation in egg size - example: the last egg laid in the nest of grackles is 45% smaller than the first. Thus, even though both eggs hatch on the same day there is variation in body size. Larger chicks will have an advantage, and the smaller chicks die off in lean years. - Asynchronous hatching - example: Snowy owls hatch eggs asynchronously so that by the time the sixth egg hatches, the first chick is 6 days old and has advantage.

Stable Hybrid Zone

Bullocks and Baltimore Orioles come into contact in the Great Plains as well. They look nothing alike but hybridize fairly readily. However, the zone of hybridization is not expanding. This results in what we call a stable hybrid zone. Two hypotheses that explain how stable hybrid zones persist are: 1. Dynamic equilibria model - hybrids are either sterile of inferior to either parent stock, and the populations is sustained by continual influx of adults from each parent stock 2. Bounded superiority model - hybrid zones coincide with intermediate ecological or environmental conditions and hybrids perform equally or better than either parent stock **Hybridization is known to occur in about 10% of bird species

What influences clutch size in birds

Food Limitation Hypothesis - clutch size is related to the number of young that parents can provide food for - optimal clutch size exists for each species or individual within a species: OFFSRING QUALITY INFLUENCES SURVIVAL. Heavier chicks at fledging have higher survival probability as measured by the percent recaptured in the woods the following spring - major explanation in altricial species - evidence: research on the Great Tits, conducted in England, show that offspring QUALITY at fledge (measured as body mass) is STRONGLY INFLUENCED BY PROVISIONING RATE (number of times a chick is fed per hour), WHICH IS STRONGLY INFLUENCED BY BROOD SIZE - latitudinal variation occurs in some species, such as song birds (tropical latitudes actually lay less eggs!)... Tropical Life History Syndrome

nidfigous

Hatchlings leave the nest immediately - capable of thermoregulation

nidicolous

Hatchlings stay in the nest - incapable of thermoregulation

Lifespan

How long birds of a species generally live Usually concentrate on their survivorship over a single year when studying this life history trait Another way to refer to this is annual survival rate We can estimate lifespan when we know annual survival rate and how it changes as individual birds get older

Rate of development

How long kids in the nest and how long after fledging do the parents continue to care for them

If offspring quality is so important, why not produce one really healthy chick?

It is a matter of diminishing returns; at some point continuing to provision one chick does not provide as much benefit to feeding two.

Natural History

Refers generally to the life style of an organism. Does mention things like clutch size, but focuses on where a species lives and how it makes its living. Tendency is to classify knowledge of habitats used, foods eaten, where the species breeds, and the timing of its annual events.

Tropical Life History Syndrome

Relatively small clutch size in tropical songbirds - they live in a benign environment that allows for more breeding attempts per season - the breeding season is longer, so they do not have to suffer through or migrate over rough winters which makes survivorship better

Clutch size

Shows some interesting differences among species and across latitudes

Number of nesting attempts per year

The frequency of reproduction in a year/lifetime

How are natural history and life history characteristics interrelated?

The habitat and habits influence the fitness of the organism

biogeography

The study of large-scale patterns in species abundance Global biogeography can be understood by examining Wallace's realms - the broad division of the globe into major zoogeographic regions based on broad patterns in fauna - reflect historical patterns influenced by continental drift

Age at first breeding

Varies from as low as 5 months (tropical house wrens) to several years after fledging (large seabirds) The majority of bird species begin breeding in the breeding season immediately after the one in which they were born

Dispersal

a one time movement of an individual away from a previous area of use. In this case, we are talking about movement of young birds away from where they were born. Dispersal distances are poorly known for most species of birds (although this is an active area of research); however we know they can vary from 0 to thousands of kilometers. In essence dispersal counteracts the influence of local adaptation. Thus, species with high philopatry and fidelity and short dispersal distances (relative to the geographic scale of its breeding distribution) are more likely in evolve complex genetic structure than a species with low philopatry or long distance dispersal.

Explain the range of zoogeographic realms and their influence on avian diversity

the broad division of the globe into major zoogeographic regions based on broad patterns in fauna - reflect historical patterns influenced by continental drift ...as continents move, natural selection is working to shape the formation of bird species Wallace originally recognized 6 biogeographic realms, then expanded to 8, then renamed 2...we only need to know the original 6 + 1 1. Oceania 2. Narcotic 3. Australasian 4. Indomalayan 5. Palearctic 6. Afrotropical 7. Neotropical

breeding site fidelity

the probability of an adult territory holder returning to the same territory (or very near by) in subsequent years (assuming it's alive to breed). Breeding site fidelity is the norm in most bird species.

Hybrid Suture Zone

the result of secondary contact may be hybridization. When this occurs at the overlapping edges of 2 species distribution, we call this a hybrid suture zone.

Natal philopatry

the tendency of an offspring to return to the area it was born. In most species only one sex is philopatric. For songbirds, it is the male. For waterfowl (ducks geese and swans) it is the female