"Clever (corvine) dinosaurs" revisited

[Stephan Pickering <stefanpickering2002@yahoo.com>]

Cf. Carolee Caffrey's excellent, ongoing research on
Corvus brachyrhynchos (her 1991 dissertation is a
major work)-- Carolee has uncanny stories to share
about these remarkably cognitive theropods. I would
cite these:
2000 Tool modification and use by an American crow.
Wilson Bulletin 112(2):283-284
2001 Goal-directed use of objects by American crows.
Wilson Bulletin 113(1):114-115
The 2000 paper lists the 8 studies published on the
subject prior to 2000, and, as Carolee notes, tool use
and creation is known among corvids, but not other
avian taxa generally. The 2001 paper lists other
studies, including the work of G.R. Hunt.
There is much these theropods can teach one: male and
female offspring stay with their parents up to four
years, assisting the raising of newer siblings. When
an offspring leaves the core family group, the older
theropod takes a younger sister or brother along. But,
the offspring usually establish their own homes next
to their parents, associate with them, and for three
generations one has a large family group of dinosaurs.
If an offspring is some distance away, the offspring
will come back for regular visits with parents and
their siblings's families.
Tool making is known, as is play behaviour (including
"playing tricks" on each other), and a vocal
repertoire surprisingly rich in cognition and signal
cues.  Family groups (usually about 8 adults) feed the
chicks in one nest. Pair-bonding is probably for life,
and mates preen each other during the entire time.
When a chick dies, documented grieving-like behaviour
transpires. Like marsupials, their diet ranges from
corn and grain sorghums, to weed seeds, and insects.
1991 Breeding group structure and the effects of
helpers in cooperatively breeding Western American
crows. Ph.D. dissertation, Univ. California Los
Angeles, 87pp
1999 Feeding rates and individual contributions to
feeding at nests in cooperative breeding Western
American crows. Auk 116(3):836-841
Now, stop and consider: we are outlining the breeding
biology of a living dinosaur...and this deserves as
much as attention from us as does cladistic analysis
of interrelationality of pre-K/T dinosaurs. And Corvus
brachyrhynchos is an excellent example: they are
intelligent dinosaurs, wary, fast, and, as Carolee
will tell you, one of the most difficult dinosaurs to
capture (2 of 3 attempts are unsuccessful). Once
captured, and banded, it is rare for this individual
to be capture a second time: they recognize any traps
erected and keep their distance, watching frustrated
dinosaurologists. The latter will try smaller devices,
changing the "bait", or waiting up to two years for a
second attempt (Carolee, as of 2002, has over 600
capture attempts to her credit).
Often, it is cats, dogs, red foxes, geese, starlings,
grackles, and blackbirds who are captured (none have
ever been injured)...and not Corvus. They will land
next to the device, foraging, but do not go near the
machine. Or they will move the bait away from the
machine so that others can feed without being
captured. A two year male adult, seeing the wire, flew
to the researchers's automobile, sat on the hood,
looking through the windshield, and, at the same time,
expostulating with a loud alarm call (I have heard
this vocalization; it is startlingly intense). The
entire family group then left...they never returned,
and were never banded for identification and study.
A similar situation took place with a female who,
flying overhead, saw the netlauncher, alarm calling to
others. She landed next to the machine (still
calling),examined it, flew off again with her family.
During Carolee's studies of these dinosaurs in
California, e.g., she caught and banded 205
individuals, only 10 of these the second time. Of the
188 dinosaurs in Oklahoma, she was able to catch only
11 the second time.
The alarm calls of these dinosaurs near human-made
machinery are analogous to their vocalizations re:
approaching predators.
Marc D. Hauser, and Carolee Caffrey, 1994.
Anti-predator response to raptor calls in wild crows,
Corvus brachyrhynchos hesperis, Animal Behaviour
48(6):1469-1471.
So, you see, living dinosaurs deserve the same
attention as their pre-K/T kin...and are in need of a
multi-part "Walking with Dinosaurs" sequel.


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