Evolutionary History: (ya = years ago)

• World's second largest living vulture (after Andean Condor)
• 3m wingspan; 12 kg
• Can fly at up to 90 km h^-1; soar to over 5000 m; and cover 200-400 km day^-1
• Carrion feeder on large carcases
• Strong pair bonding
• Form close, highly interactive, social groups
• Nests on inaccessible ledges and caves on cliffs

 Causes of Decline (long-term):

• Pleistocene glaciations
• Repeated declines and extinctions of "mega-fauna" carcases
• Repeated habitat restriction
• Climatic trends
• Hunting by first humans (about 12,000 years ago) completed Pleistocene mega-faunal extinctions
• Extinctions of mega-herbivores drastically expanded closed forest habitats, reduced open grassland habitats

Causes of Decline (since European contact):

• Hunting
• Loss of remaining food via reduction, local extinction of medium herbivores (e.g. deer)
• Replacement sheep and cattle provided few carcases
• Target of misplaced predator and "vermin" control
• Poisoning from predator-control poisons
• Thin-shelled eggs, abnormal reproduction from bio-accumulated pesticides (e.g. DDT)
• Lead poisoning from accumulated bullets (from carcases) in crop and gizzard
• Electrocution in power lines
• Poisoning from drinking antifreeze, oil, etc.

1. Complex sets of LHC, with close juxtaposition of extreme "r-selected" and extreme "K-selected" traits simultaneously, sequentially, or alternating at different time in the life cycle.

2. Such combinations cannot be explained by r- and K-selection models

3. A rarely stated assumption of r- and K-selection models is that natural selection shapes LHC during times of positive or zero population growth under favorable conditions. either when the population is growing rapidly at r, or when it is maintaining its maximum density at K.

4. This assumption cannot be true for the California Condor, which has probably experienced negative growth for much of the last 2 Ma, and has certainly experienced increasing population declines over the last 10Ka. Within the last 500 y, rates of decline have accelerated.

5. One plausible explanation of the Condor's LHC is that they have evolved primarily during negative population growth in response to natural selection by unfavorable conditions, and that such selection has increased in intensity as the population approaches extinction.

6. Natural selection favors traits of the individuals who leave relatively more descendants in future generations. This remains true even in declining populations where, on average, individuals do not even replace themselves (< 1 descendent in next generation).

7. In declining populations, an individual leaves more genes in a population through an extended lifespan that keeps its own genes in the population and provide repeated opportunities for reproduction (that are more likely to fail than succeed), than it will if it maximizes reproductive output during a short life-time. Repeated reproductive attempts increase the probability that at least one will be under sufficiently "favorable" conditions that the progeny reaches maturity

8. Viewing the condor's life history as evolutionary responses that slow the rate of population decline and delay extinction eliminate many apparent contradictions:

• Traits favoring adult persistence are favored because they are "more valuable" than juveniles
• Energy and resources devoted to reproduction are minimized, because this will usually be unsuccessful. Minimal reproductive costs enhance adult physiological fitness
• The switch from little parental care to intense parental care makes sense. Before fledging, adults are likely to be injured or killed if they try to protect chicks on the ground. Once flying, the parents can protect, feed and train their chick at little risk to themselves. At fledging the chick becomes "more valuable" than the adult for the first time.

The california condor almost went extinct because legal and philosophical battles between advocates of two very different approaches to conservation of endangered species prevented establishment of the captive breeding program for many years, until only 27 birds remained alive. It was feared they could not live and breed in captivity. But after capturing it was discovered:

• They mate readily in captivity
• If eggs are removed to incubators, females will produce multiple eggs in a season
• In captivity, females will lay eggs every year
• Survival, growth and development is excellent in captivity
• Family and larger social groups are established, and parental care is maintained
• Some behaviors that cannot be learned from parents in captivity, can be taught to chicks using human surrogates and other species (e.g. Andean condor)
• Positive and aversion training can continue for juveniles in field cages and after release
• Juveniles can survive, growth and form social groups after release.
• Three apparently permanent wild populations have now been re-established
• It will be about 5 years before it's known whether they will reproduce successfully