Citizen science, and the limits thereof

One of my neighbors sent me a copy of a list that she was given by the people who sold her her house. They told her they saw all these species in El Cerrito Hillside Natural Area. At first was excited to see this list, and the first several species on there are quite reasonable, but a more careful look significantly lowered my level of confidence in these observations. This is a perfect example of why "citizen science" projects that rely on non-experts to gather natural history data require great care. Below I have pasted in the list, with some comments.

chestnut-backed chickadee
common bushtit
turkey vulture
cooper's hawk
american kestrel
red-tailed hawk
common crow
common raven
great-horned owl
ruby-crowned kinglet
woodthrush (Does not occur in CA, probably Hermit Thrush)
red-shafted flicker
winter wren
hairy woodpecker
downy woodpecker
robin
brown towee (Californa Towhee)
rufous-sided towee (Spotted Towhee)
oregon junco (Dark-Eyed Junco)
purple finch
house finch
pine siskin
wilson's warbler
tennessee warbler (does not occur in CA, Orange-Crowned Warbler)
american goldfinch
lesser goldfinch
lawrence's goldfinch
mockingbird
plain titmouse (Oak Titmouse)
scrub jay
steller's jay
mexican jay (Does not occur in CA, probably juv. scrub-jay)
cedar waxwing
western wood pewee
mourning dove
bead-tailed pigeon (Band-tailed Pigeon)
fox sparrow
savannah sparrow
harris's sparrow (Does not occur in CA, probably House Sparrow)
golden-crowned sparrow
starling
anna's hummingbird
allen's hummingbird
black phoebe
wrentit
marsh hawk (Same as Northern Harrier, listed below)
swainsons's thrush (possible)
mississippi kite (Does not occur in CA, probably Northern Harrier)
rufous hummingbird (nearly impossible to tell from Allen's except in hand)
canada goose
brown pelican (in park or flying in distance over bay?)
slate-colored junco (same as junco listed above)
warbling vireo
lazuli bunting (possible)
western tanager
bluegray gnatcatcher
empidonax flycatcher
bewick's wren
yellow-rumped warbler
townsend's warbler
hermit thrush
myrtle warbler (same as Yellow-rumped arbler)
osprey
beardless flycatcher (not found in CA)
red-breasted nuthatch
white warbler (not a real species, no idea)