1-4- Swift & Marzluff 2015

Question 1

What happened in the 72 hours after observing novel humans paired with a dead crow, a red-tailed hawk or a hawk with a dead crow?

Answer 1

Crows mobbed and increased the time to approach food

Question 2

On the day the stimulus was presented, the number of trials that resulted in mobbing and
avoidance of the food was strongest when what happened?

Answer 2

On the day the stimulus was presented, the number of trials that resulted in mobbing and
avoidance of the food was strongest when crows were presented a hawk with a dead crow

Question 3

Crows use the proximity of a human to predators, to dead conspecifics and to
predators with dead conspecifics as cues to learn to recognize and subsequently scold the associated
human after only one training event, and that this association can last how long?

Answer 3

6 weeks

Question 4

Which animals congregate around dead conspecifics?

Answer 4

Black-billed magpies, western scrub-jays, chimpanzees, african elephants and bottlenose dolphins

Question 5

Which animals respond to dead conspecifics in the absence of artificial distress calls?

Answer 5

Western scrub-jays

Question 6

following carcass removal, what did scrub-jays show?

Answer 6

following carcass removal, scrub-jays show

reduced feeding activity in the area for 24 h.

Question 7

How can fear be extinguished?

Answer 7

Fear can be extinguished, however, through repeated exposure to the conditioned
stimulus without reinforcing its predictive value of the unconditioned stimulus

Question 8

what was experiment 1?

Answer 8

To test
danger learning, we conducted three experiments on wild crows. In
experiment 1, we examined (1) whether the sight of a dead
conspecific is sufficient to elicit alarm calling and recruitment, or
whether the presence of an unconditioned predator is also necessary, (2) whether crows learn areas associated with these dangers
and subsequently avoid them, (3) whether crows use dead conspecifics to identify novel predators and, if so, how this process
compares to conditioned learning when novel predators are paired
with unconditioned stimuli (hawks), and (4) whether fear extinction can be achieved with a minimum of three additional exposures.

Question 9

What was experiment 2?

Answer 9

For experiment 2, we determined whether a dead conspecific
is a more salient source of dangerous information than a similarly
sized, dead heterospecific

Question 10

What was experiment 3?

Answer 10

In experiment 3, we compared responses of rock pigeons and crows to dead conspecifics.

Question 11

what were the three phases of each experiment?

Answer 11

conditioning, stimulus presentation and post-exposure

Question 12

We assumed that no more than ___ adult birds occupied each territory, as helping behaviour occurs infrequently in crow populations
in the northwestern United States

Answer 12

We assumed that no more than two adult birds occupied each territory, as helping behaviour occurs infrequently in crow populations
in the northwestern United States

Question 13

Crows received a 2:1 mix of what?

Answer 13

Crows received a 2:1 mix of raw, unshelled peanuts and cheese puffs

Question 14

Pigeons received a 2:1 mix of what?

Answer 14

Pigeons received a 2:1 mix of

birdseed and crumbled white bread.

Question 15

After providing food, the observer monitored the food pile from ____ m away, for up to ____, and measured the birds’ latency to approach within ___m of
the food pile (‘food discovery time’).

Answer 15

observer monitored the food pile from 15-25 m away, for up to 2.5 h, and measured the birds’ latency to approach within 2 m of the food pile (‘food discovery time’).

Question 16

What was the conditioning phase?

Answer 16

Once the birds at each site approached the food within the 2.5 h observation period for 3 consecutive days (in most tests, birds met
the criterion in 3 days; in seven tests, birds took up to 10 days to meet the criterion), we began the stimulus presentation phase on the following day (day 4).

Question 17

During the stimulus presentation phase, we _____ _____ ____ _____, after which a volunteer ______________________

Answer 17

During the stimulus presentation phase, we provided food as normal, after which a volunteer exposed an experimental or a control stimulus 2 m from the food pile

Question 18

Volunteers

wore one of six ______ _____ with _____ _____

Answer 18

Volunteers

wore one of six realistic facemasks with neutral expressions

Question 19

Why did volunteers wear a white sign

around their neck that read ‘UW CROW STUDY’?

Answer 19

to limit interruptions by pedestrians or police

Question 20

During stimulus presentation,
the data collector recorded instances and durations of _____ and
typical crow ____ ____, and the number ____ _____ ____ _____

Answer 20

During stimulus presentation,
the data collector recorded instances and durations of scolds and
typical crow contact calls, and the number of birds present within
25 m of the stimulus

Question 21

what was mob formation?

Answer 21

the presence of

more than two scolding individuals within 25 m of the stimulus.

Question 22

what was mob size?

Answer 22

We calculated mob size as the maximum number of individuals

present during the stimulus event.

Question 23

why did they not determine
whether all individuals within a mob actively scolded beyond the
three-bird minimum?

Answer 23

Because mobs are highly mobile and most birds were not individually marked

Question 24

The volunteer removed the stimulus ___min after the first bird perched within __ m of the stimulus and was
observed gazing towards the experimental set-up (‘stimulus discovery time’).

Answer 24

The volunteer removed the stimulus 30 min after the first bird perched within 25 m of the stimulus and was
observed gazing towards the experimental set-up (‘stimulus discovery time’).

Question 25

Following stimulus removal, for up to __h, the
observer recorded the birds’ latency to approach within __m of the
food pile (‘food discovery time’).

Answer 25

Following stimulus removal, for up to 2.5 h, the
observer recorded the birds’ latency to approach within 2 m of the
food pile (‘food discovery time’).

Question 26

We removed all but a small

amount (_____) of food after ___-h

Answer 26

We removed all but a small

amount (five pieces) of food after 2.5 h

Question 27

. If birds approached the pile
in the presence of the stimulus, we recorded the food discovery
time as ___s

Answer 27

. If birds approached the pile
in the presence of the stimulus, we recorded the food discovery
time as 0 s.

Question 28

The observer used ____, ____, ___and ___ ___ to discriminate between hatch-year and older birds

Answer 28

The observer used plumage, profile, voice and mouth

lining to discriminate between hatch-year and older birds

Question 29

Only birds

older than 1 year of age were counted for what?

Answer 29

Only birds
older than 1 year of age were counted for stimulus discovery time,
food discovery time and mob or group size.

Question 30

During the post-exposure phase, on days __-__, we split the

experiment into two trial types

Answer 30

During the post-exposure phase, on days 5e7, we split the

experiment into two trial types

Question 31

what was trial type A

Answer 31

In trial type A, we
continued to provide food (as described above) to test for site
aversion.

Question 32

what was trial type B?

Answer 32

In trial type B, following standard feeding by the observer
(as during conditioning), a volunteer wearing the same mask as
seen during the stimulus exposure phase arrived and stood 2 m
from the food pile.

Question 33

What was the difference between A and B?

Answer 33

n trial type B, following standard feeding by the observer
(as during conditioning), a volunteer wearing the same mask as
seen during the stimulus exposure phase arrived and stood 2 m
from the food pile. The experimental procedure during test trial B
otherwise matched that of the stimulus exposure phase, allowing
us to test for novel predator learning and to evaluate the influence
of varying levels of exposure to danger on fear extinction

Question 34

which experiment used both trial types?

Answer 34

experiment 1

Question 35

what trial type did experiments 2 and 3 use?

Answer 35

Experiments 2 and 3 used trial

type A during the post-exposure phase.

Question 36

marked individuals were banded __ years before the

onset of the present experiment.

Answer 36

marked individuals were banded 5 years before the

onset of the present experiment.

Question 37

Experimental locations were

established ___-___m from nest sites to limit nest disturbance.

Answer 37

Experimental locations were

established 35-45 m from nest sites to limit nest disturbance.

Question 38

How many sites were there and how many territorial pairs?

Answer 38

In 2013 and 2014, we selected 17 independent sites and, within
each site, identified seven to nine territorial pairs

Question 39

In
April-June, we used ___ ___ to define the _____ for tests,
and established specific test locations ___-___m from the nest tree

Answer 39

In
April-June, we used nesting areas to define the locations for tests,
and established specific test locations 35-45 m from the nest tree

Question 40

During July-September, we identified test _____by the presence of ____ ____or the consistent ____ ___ ____ ____ ____

Answer 40

During July-September, we identified test locations by the presence of fledged young or the consistent presence of an adult pair.

Question 41

American crow territories in the urban core are smaller than what?

Answer 41

American crow territories in the urban core are smaller than their
suburban counterparts

Question 42

what was the minimum distance between two test locations?

Answer 42

90m

Question 43

what was the median distance between two test locations

Answer 43

430m

Question 44

During the stimulus presentation phase of the experiment, birds
received one of five stimuli . what were they?

Answer 44

3 dangerous:

• dead crow + mask
• hawk + mask
• dead crow + hawk + mask

2 control:

• person in mask
• food only

Question 45

Between sites, why did they vary the

sequence of stimulus presentations ?

Answer 45

Between sites, we varied the
sequence of stimulus presentations so that the order of control and
dangerous stimuli were counterbalanced.

Question 46

. In 2014, what was not used?

Answer 46

. In 2014, the mask-only

control was not used

Question 47

what happened because the mask only control was to used in 2014?

Answer 47

. In 2014, the mask-only
control was not used, and thus fewer sites were tested in 2014
than in 2013.

Question 48

how many taxidermy crows and hawks were there?

Answer 48

We used three identically prepared taxidermy mounts
of crows (randomized across trials) but only a single, mounted redtailed hawk.

Question 49

Because of time constraints, in ___ of cases, birds were present
during the stimulus set-up and witnessed the unmasked volunteer
interact with the avian stimuli.

Answer 49

Because of time constraints, in 43% of cases, birds were present
during the stimulus set-up and witnessed the unmasked volunteer
interact with the avian stimuli.

Question 50

why did they not believe witnissing the set-up biased the response?

Answer 50

Given that humans were common at
each site and that their presence with or near dangers was already
an element of our experimental design,

Question 51

what happened (more detail) in trial type A?

Answer 51

in trial type A (N =74, which
included 17 food-only controls), we provided food as during the
conditioning phase.

Question 52

what happened (more detail) in trial type B?

Answer 52

In trial type B (N =57), after the observer
provided food, a colleague wearing the same mask used during the
stimulus presentation phase immediately arrived and stood 2 m
from the food pile.

Question 53

how did they test longevity of response?

Answer 53

scolding, diving
or mobbing the masked person, or refusing to approach within 2 m
of the food pile for the full 2.5 h after the masked person’s departure

Question 54

We administered up to ___ weekly

tests (longevity tests 1-6),

Answer 54

We administered up to six weekly

tests (longevity tests 1-6),

Question 55

because of time constraints, only ___
of the 17 sites (one each from Redmond and Kirkland, and all nine
Seattle sites; 77 of 114 potential territories) were tested beyond the
first longevity test.

Answer 55

because of time constraints, only 11
of the 17 sites (one each from Redmond and Kirkland, and all nine
Seattle sites; 77 of 114 potential territories) were tested beyond the
first longevity test.

Question 56

when were tests discontinued?

Answer 56

Tests were discontinued prior to completing all

six tests if the birds became unresponsive.

Question 57

Tests in trial type A
began __ ____ from the ___ ____ _____ provided that
the birds had responded during the stimulus presentation phase

Answer 57

Tests in trial type A
began 1 week from the stimulus presentation phase provided that
the birds had responded during the stimulus presentation phase

Question 58

In type A in experiment 1, how many birds did not respond?

Answer 58

24 of 74 did not respond: N =5 mask-only controls, N =17

food-only controls

Question 59

Birds in trial type B were tested __ ____ from
the last day of the _______ ____ provided they were still
responding at that time

Answer 59

Birds in trial type B were tested 1 week from
the last day of the post-exposure phase provided they were still
responding at that time

Question 60

in experiment 1 type b, how many birds stopped responding?

Answer 60

20 of 57 stopped responding; of those,

N =5 were mask-only controls

Question 61

The first four longevity tests followed what?

Answer 61

The first four longevity tests followed the format of the post-exposure phase in trial type B;

Question 62

If birds remained
responsive during the longevity test in week 4, during the fifth
longevity test, what did they do?

Answer 62

If birds remained
responsive during the longevity test in week 4, during the fifth
longevity test we did not provide food and instead presented either
a person wearing the conditioned mask or a novel, unconditioned
mask followed approximately 6-9 h later by the opposite mask, to
test for recognition of the dangerous mask.

Question 63

Following the first

encounter with an adult bird, the masked volunteer did what?

Answer 63

Following the first
encounter with an adult bird, the masked volunteer walked around
the approximated home range of the birds (based on observations
by volunteers and the primary observer) for 30 min, and the
observer recorded the number of crows within 25 m and any instances of scolding.

Question 64

what happened if the birds responded during the fifth test?

Answer 64

. If the birds responded during the fifth test, on
week 6 we presented birds with the dangerous mask at a distance
of 25, 50 or 75 m from the food pile

Question 65

why did they present birds with the dangerous mask at a distance
of 25, 50 or 75 m from the food pile

Answer 65

to test for

context-dependent learning of the masked volunteer.

Question 66

The observer
recorded the number of birds within __m of the food pile and the
masked person.

Answer 66

The observer
recorded the number of birds within 25 m of the food pile and the
masked person.

Question 67

what was stimulus discovery?

Answer 67

the time the first bird came within 25 m of the stimulus

and was observed gazing towards it

Question 68

what was food discovery?

Answer 68

the first time a bird approached the food pile following stimulus
discovery

Question 69

The masked person left the area __min following

stimulus discovery.

Answer 69

The masked person left the area 30 min following

stimulus discovery.

Question 70

when did they do experiment 2?

Answer 70

august-september 2014

Question 71

what was the distance between sites in experiment 2?

Answer 71

a minimum distance of 400 m from all previous experiments. Sites were 1000 m from each other.

Question 72

what happened after the conditioning phase in experiment 2?

Answer 72

fter the conditioning
phase, the crows were presented with a masked person holding a
taxidermy-mounted ‘dead’ pigeon 2 m from the food pile

Question 73

when did they do experiment 3?

Answer 73

December 2013 and AugusteSeptember

of 2014.

Question 74

why did behavioural differences

due to breeding did not differ between winter and summer tests?

Answer 74

Since pigeons breed year-round, behavioural differences

due to breeding did not differ between winter and summer tests.

Question 75

what was the distance between sites in experiment 3?

Answer 75

We used six unique sites at least 350 m from previous crow experiments, and 1000 m from each other,

Question 76

what was the difference between 2013 and 2014 in experiment 3?

Answer 76

Experiments conducted in 2013 used a fresh

pigeon carcass, and experiments in 2014 used a taxidermymounted ‘dead’ pigeon.

Question 77

Experiment 1

Across years, territorial adults scolded during ___ of trials that
presented dangerous stimuli (N =102 tests),

Answer 77

Across years, territorial adults scolded during 96% of trials that
presented dangerous stimuli (N ¼ 102 tests),

Question 78

Experiment 1
only __%
scolded during mask-only control presentations (N =12 tests)

Answer 78

only 17%

scolded during mask-only control presentations (N ¼ 12 tests)

Question 79

Experiment 1

__% scolded during food-only control presentations (N ¼ 17 tests).

Answer 79

0% scolded during food-only control presentations (N ¼ 17 tests).

Question 80

Experiment 1

Of
those crows that did not scold when presented with a danger, ___
observed a dead conspecific, ___observed a hawk, and ___
observed a hawk with a dead crow.

Answer 80

Of
those crows that did not scold when presented with a danger, two
observed a dead conspecific, one observed a hawk, and one
observed a hawk with a dead crow.

Question 81

Experiment 1

Neither __-___ nor ___-____ control tests resulted in
mobbing.

Answer 81

Neither food-only nor mask-only control tests resulted in

mobbing.

Question 82

Experiment 1

what primarily drove the result of the likelihood of mobbing differed between the three
dangerous stimuli

Answer 82

The response of crows that saw a hawk with a dead conspecific
primarily drove this result

Question 83

Experiment 1

Was hawk + dead crow versus hawk
alone significantly different

Answer 83

hawk þ dead crow versus hawk

alone were not significantly different

Question 84

Experiment 1

After mob formation, crows spent more time constantly
____ the hawk with a dead crow (mean ± SE =11.1 ± 1.3 min)
than they did the dead crow (7.5 ± 1.3 min) or the hawk
(6.1 ± 1.5 min) alone, but this difference __________

Answer 84

After mob formation, crows spent more time constantly
scolding the hawk with a dead crow (mean ± SE ¼ 11.1 ± 1.3 min)
than they did the dead crow (7.5 ± 1.3 min) or the hawk
(6.1 ± 1.5 min) alone, but this difference was not significant

Question 85

Experiment 1

The number of birds present
during stimulus presentation depended on the type of stimulus. How?

Answer 85

The number of birds present
during stimulus presentation depended on the type of stimulus
(F4,126 ¼ 8.69, P < 0.001; Fig. 4). More birds were present during
presentation of the hawk þ dead crow than during presentation of
the dead crow (mean difference ¼ 6.35; Tukey HD: P ¼ 0.002) or
the hawk (mean difference ¼ 5.85; Tukey HD: P ¼ 0.005)

Question 86

Experiment 1

. In trials
that resulted in mobbing, mob size differed with stimulus type
(ANOVA: F2,75 =3.53, P =0.034), but this effect was driven solely
by what?

Answer 86

. In trials
that resulted in mobbing, mob size differed with stimulus type
(ANOVA: F2,75 ¼ 3.53, P ¼ 0.034), but this effect was driven solely
by the difference between hawk þ dead crow versus hawk (mean
difference ¼ 5.25; Tukey HD: P ¼ 0.043).

Question 87

Experiment 1

There was ______ in mob size during presentations of the hawk + dead
crow versus the dead crow or the dead crow versus the hawk

Answer 87

There was no significant
difference in mob size during presentations of the hawk þ dead
crow versus the dead crow (mean difference ¼ 4.47; Tukey HD:
P =0.13) or the dead crow versus the hawk (mean difference =0.78; Tukey HD: P =0.94).

Question 88

Experiment 1

During the 2.5 h immediately following presentation of the
stimulus, what % of crows exposed to a dangerous stimulus did not return to the food pile?

Answer 88

17%

Question 89

Experiment 1

All crows that received a
___ ____ returned to the food

Answer 89

All crows that received a
control treatment (N ¼ 29 tests) returned to the food

Question 90

Experiment 1

Crows
differed in avoidance of particular stimuli . what drove this effect?

Answer 90

Crows’ avoidance of the
hawk þ dead crow primarily drove this effect

however,
dead crow versus hawk + dead crow were not different

Question 91

Trial type A

During the stimulus presentation phase, __% of birds avoided the
food for the 2.5 h following stimulus removal, whereas during the
post-exposure phase, ___________

Answer 91

During the stimulus presentation phase, 17% of birds avoided the
food for the 2.5 h following stimulus removal, whereas during the
post-exposure phase, most birds eventually approached the food

Question 92

Trial type A

Regardless of the dangerous stimulus seen during the stimulus presentation phase, crows showed similar increases in what?

Answer 92

presentation phase, crows showed similar increases in latencies to
approach the food pile during the post-exposure phase relative to
the conditioning phase

Question 93

Trial type A

, birds
exposed to dangerous stimuli showed a larger change in latency to
________

Answer 93

, birds
exposed to dangerous stimuli showed a larger change in latency to
approach the food pile (relative to the conditioning phase) than did
birds in the control treatment

Question 94

Trial type A

Comparing only the post-exposure phase, birds exposed to danger
took longer to approach food than did who?

Answer 94

control birds

Question 95

Trial type B

In trial type B, crows’ change in latency to approach the food pile
during the post-exposure phase did not vary with the type of
dangerous stimulus

therefore, what did they do?

Answer 95

we lumped all
dangerous stimuli into a single ‘danger’ treatment and lumped the
two controls into a single ‘control’ treatment.

Question 96

Trial type B

The difference in latency to approach the food pile during the conditioning phase and
the post-exposure phase was greater for crows that saw a
____ ____than for crows that saw a ____ _____

Answer 96

The difference in latency to approach the food pile during the conditioning phase and
the post-exposure phase was greater for crows that saw a
dangerous stimulus than for crows that saw a control stimulus

also took longer to approach food

Question 97

Longevity tests

Crows that viewed a dangerous stimulus were equally likely to
respond in the first longevity test to the ____ ____ ___ ___ regardless of the type of unconditioned stimulus
or the trial type

Answer 97

Crows that viewed a dangerous stimulus were equally likely to
respond in the first longevity test to the previously conditioned
masked person regardless of the type of unconditioned stimulus
or the trial type

Question 98

Longevity tests

Even after 6 weeks of
additional weekly exposures, birds in trial type B showed no
significant difference in ____ ____ compared to those in trial
type A and they were no more
likely to respond to ____

Answer 98

Even after 6 weeks of
additional weekly exposures, birds in trial type B showed no
significant difference in fear extinction compared to those in trial
type A and they were no more
likely to respond to the person associated with any one of the three
dangers

Question 99

Longevity tests

During the fifth longevity test
(where crows saw a dangerous stimulus or a person wearing a
neutral mask, then a dangerous mask), birds were more likely to
scold the _____ than the ______

Answer 99

During the fifth longevity test
(where crows saw a dangerous stimulus or a person wearing a
neutral mask, then a dangerous mask), birds were more likely to
scold the dangerous mask than the neutral mask

Question 100

Longevity tests

. During the sixth longevity test,
where crows saw the masked person previously associated with
danger either 25 m (N ¼ 13), 50 m (N ¼ 10) or 75 m (N ¼ 8) from
the food pile, the crows were no more likely to stop responding
than they had been during _____ ___

Answer 100

. During the sixth longevity test,
where crows saw the masked person previously associated with
danger either 25 m (N ¼ 13), 50 m (N ¼ 10) or 75 m (N ¼ 8) from
the food pile, the crows were no more likely to stop responding
than they had been during week 4

Question 101

Longevity tests

crows’ failure to respond to the masked
person did not differ with ________

Answer 101

crows’ failure to respond to the masked

person did not differ with distance to the food pile

Question 102

Seasons & carryover

did the season the brids were tested in effect the likelihood of scolding

Answer 102

The season (AprileJune, N ¼ 65; JulyeSeptember, N ¼ 37) in
which birds were tested did not influence the likelihood of scolding
the dangerous stimuli

Question 103

Seasons & carryover

The
proportion of birds that mobbed during AprileJune tests (N ¼ 47 of
65) was _____ ____ than those tested during JulyeSeptember
(N ¼ 31 of 37), however,____________

Answer 103

The
proportion of birds that mobbed during AprileJune tests (N ¼ 47 of
65) was slightly lower than those tested during JulyeSeptember
(N ¼ 31 of 37), however, this difference was not significant

The same trend could be seen with respect to
changes in latency to approach food in both type A (repeated
measures ANOVA: F1,49 ¼ 1.48, P ¼ 0.23) and type B

Question 104

Seasons & carryover

Of 24 marked individuals, how many birds were
recruited to mob at a different test site during stimulus presentation?

Answer 104

f 24 marked individuals, only one previously tested bird was
recruited to mob at a different test site during stimulus presentation, although six marked birds were seen on other days.

Question 105

Seasons & carryover

did proportion of brids that mobbed during first and last week of testing differ between sites?

Answer 105

proportion of birds that mobbed the dangerous stimulus during the
first week of testing (N ¼ 7 of 12 birds) and the last week of testing
(N ¼ 9 of 13 birds) did not differ across sites

Question 106

Seasons & carryover

Crows tested first within a site tended to take longer to approach
food after exposure to danger than those tested last, but _________________________-

Answer 106

Crows tested first within a site tended to take longer to approach
food after exposure to danger than those tested last, but this difference was not significant

Question 107

Seasons & carryover

Furthermore, crows in control territories that
were either greater than (N ¼ 8) or less than (N ¼ 8) 400 m from a territory where a dangerous stimulus had previously been
deployed___ ___ ____ in their change in latency to approach food
between the conditioning phase and the post-exposure phase

Answer 107

territory where a dangerous stimulus had previously been
deployed did not differ in their change in latency to approach food
between the conditioning phase and the post-exposure phase

Question 108

Experiment 2

While 94% of the crows scolded when they saw a dead
conspecific (N ¼ 34 tests), only ___% of the crows scolded in
response to a dead pigeon

Answer 108

40%

Question 109

Experiment 2

Even in cases where crows scolded in response to
the dead pigeon, they did so _____ times
than in response to a dead conspecific

Answer 109

Even in cases where crows scolded in response to
the dead pigeon, they did so far fewer times (mean ± SE ¼ 7 ± 1.26)
than in response to a dead conspecific (63.74 ± 9.89).

Question 110

Experiment 2

Crows
exposed to a dead pigeon did not ____, unlike the majority of those
that saw a dead crow

Answer 110

Crows
exposed to a dead pigeon did not mob, unlike the majority of those
that saw a dead crow

Question 111

Experiment 2

Following exposure to a
dead conspecific, crows in trial type A took longer to approach the
food during the post-exposure phase relative to the conditioning
phase, more than did crows confronted with __ _____ ____

Answer 111

Following exposure to a
dead conspecific, crows in trial type A took longer to approach the
food during the post-exposure phase relative to the conditioning
phase, more than did crows confronted with a dead pigeon

Question 112

Experiment 2

During the post-exposure phase,
crows that saw a dead conspecific took longer to ____ _____
than crows that saw a dead pigeon

Answer 112

During the post-exposure phase,
crows that saw a dead conspecific took longer to approach food
than crows that saw a dead pigeon

Question 113

Experiment 3

Pigeons flocked to food in the presence of a masked person
holding the dead pigeon in ___% of cases (N ¼ 6 tests)

Answer 113

66%

Question 114

Experiment 3

crows never ____________________

Answer 114

crows never approached the food in the presence of a masked

person holding a dead crow

Question 115

Experiment 3

Sight of a dead conspecific had
different effects on the ____ __ ______ to approach the food pile
in pigeons relative to crows

Answer 115

Sight of a dead conspecific had
different effects on the change in latency to approach the food pile
in pigeons relative to crows

Question 116

Experiment 3

crows delayed their approach to the food pile after stimulus
exposure, pigeons ____________

Answer 116

crows delayed their approach to the food pile after stimulus

exposure, pigeons approached the food pile faster during the postexposure phase than during the conditioning phase

Question 117

wild

crows use the bodies of dead conspecifics as an indication that _______

Answer 117

wild
crows use the bodies of dead conspecifics as an indication that an
area is dangerous

Question 118

we show that crows make inferences about ____ _____ based on a novel predator’s _________

Answer 118

we show that crows make inferences about novel predators based on a novel predator’s proximity to dead conspecifics and to hawks.

Question 119

how long do inferences about novel predators last?

Answer 119

up to 6 weeks

Question 120

what are the purposes of mobbing?

Answer 120

chastising the predator , displaying dominance
, or social learning of the dangerous person
or place

Question 121

Our finding that crows scolded and mobbed people holding dead
crows, without playback of conspecific alarm vocalizations, supports the assessment that dead crows represent ____ _____ ____

Answer 121

Our finding that crows scolded and mobbed people holding dead
crows, without playback of conspecific alarm vocalizations, supports the assessment that dead crows represent a salient danger.

Question 122

control presentations of people or food rarely elicited

_____ by individual crows and never escalated to ____,

Answer 122

control presentations of people or food rarely elicited

scolding by individual crows and never escalated to mobbing,

Question 123

like ____

______, the discovery of a dead conspecific is effective at triggering typical antipredator behaviours

Answer 123

like western

scrub-jays, the discovery of a dead conspecific is effective at triggering typical antipredator behaviours

Question 124

Crows were more likely to mob and to avoid the food pile more
consistently over the next ___h in response to a hawk with a dead
crow than in response to either a hawk or a dead crow alone.

Answer 124

Crows were more likely to mob and to avoid the food pile more
consistently over the next 2.5 h in response to a hawk with a dead
crow than in response to either a hawk or a dead crow alone.

Question 125

In crows, exposure to a

hawk results in activation of the___ _____

Answer 125

In crows, exposure to a

hawk results in activation of the caudal nidopallium

Question 126

Our finding
that crows were less likely to mob if a hawk was observed without
conspecific prey supports the conclusion of what?

Answer 126

Our finding
that crows were less likely to mob if a hawk was observed without
conspecific prey supports the conclusion that crows are sensitive to
predator behaviour (with or without prey) and subsequently adjust
the aggressiveness of their mobbing response

Question 127

After exposure to a human with a dead crow, or a hawk, or a
hawk with crow remains, the crows in both trial types A and B took
longer to _________ than they did during the ____

Answer 127

After exposure to a human with a dead crow, or a hawk, or a
hawk with crow remains, the crows in both trial types A and B took
longer to approach food in the locations associated with these
events than they did during the conditioning phase.

Question 128

When we
compared differences only in the post-exposure phase between
control stimuli and dangerous stimuli, we again found that crows
exposed to danger ________ with the event, although this difference was more highly
significant in trial type __

Answer 128

When we
compared differences only in the post-exposure phase between
control stimuli and dangerous stimuli, we again found that crows
exposed to danger look longer to approach food locations associated with the event, although this difference was more highly
significant in trial type B

Question 129

When we
compared differences only in the post-exposure phase between
control stimuli and dangerous stimuli, we again found that crows
exposed to danger look longer to approach food locations associated with the event, although this difference was more highly
significant in trial type B.

what does this suggest

Answer 129

suggesting that the ongoing presence of
the ‘conditioned person’ may have exaggerated the fear response to
the place.

Question 130

Our findings
indicate that crows learn the spatial context associated with a brief (30 min) dangerous event and that changes in latency to approach
food in these areas can last for up to __ h after the cadaver and/or
predator is removed

Answer 130

72 h

Question 131

crows’ change in latency
to approach food before and after stimulus presentation did not
differ with what?

Answer 131

crows’ change in latency
to approach food before and after stimulus presentation did not
differ with the type of danger stimulus

Question 132

One week following presentation of a novel human paired with
a dangerous stimulus, more than half of birds in each trial type
_____or ___ ____ the person or refused to approach food for
___ h after the person had left.

Answer 132

One week following presentation of a novel human paired with
a dangerous stimulus, more than half of birds in each trial type
scolded or dove towards the person or refused to approach food for
2.5 h after the person had left.

Question 133

in __% of cases, the crows in sites eligible for all longevity tests
continued to respond for up to 6 weeks

Answer 133

in 38% of cases, the crows in sites eligible for all longevity tests
continued to respond for up to 6 weeks

Question 134

Our finding that the type of
dangerous stimulus associated with a person did not influence the
crows’ response to the person 1 week later, or up to 6 weeks later,
suggests what?

Answer 134

that dead crows and predators are equivalent at triggering

fear conditioning.

Question 135

Fear extinction of crows that received three additional exposures to the _____ did not differ from that of _____

Answer 135

Fear extinction of crows that received three additional exposures to the conditioned human stimulus without the unconditioned stimulus (trial type B) did not differ from that of crows that
received no additional exposure (trial type A).

Question 136

Fear extinction of crows that received three additional exposures to the conditioned human stimulus without the unconditioned stimulus (trial type B) did not differ from that of crows that
received no additional exposure (trial type A). T

what does this suggest

Answer 136

This suggests that

subsequent exposures to conditioned stimuli alone do not immediately lead to fear habituation in wild crows.

Question 137

a dangerous person

positioned 25, 50 or 75 m from the food during week 6 did what?

Answer 137

a dangerous person
positioned 25, 50 or 75 m from the food during week 6 did not
result in a higher number of extinctions than was observed during
week 4, when the food and the person were last paired together

Question 138

ws there a difference in extinction between the differences

Answer 138

a dangerous person
positioned 25, 50 or 75 m from the food during week 6 did not
result in a higher number of extinctions than was observed during
week 4, when the food and the person were last paired together

Question 139

experiment 2 was in contrast to what other species?

Answer 139

western scrub-jays

Question 140

In our experiments, __% of crows
remained wary of the person or the place associated with death of a
conspecific for 6 weeks.

Answer 140

38%