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WESTERN SCRUB-JAY FUNERALS

It is every animal’s nature to fight for their safety. One environmental cue that they use is detecting a dead

conspecific, it is where they avoid sites with numerous remains of their same species.

TERMINOLOGIES

• Western scrub-jay - Robin-sized bird, but large strong bill and long tail make it appear larger.

• Cacophonous Aggregation (CA) – unpleasant sound produced by group of jays around a dead conspecific

• Dead conspecific – A dead animal of the same type

Jays usually feed on peanuts

EXPERIMENTS . . .

Methods:

WHO: Western Scrub - Jay

WHAT: “Funerals”

WHY: Cacophonous aggregation in response to dead conspecifics

WHEN: Every morning from June 2007 – September 2009

WHERE: Davis California, USA

HOW: through the help of the individual home owners

Novelty object at the middle - resembles a dead Jay

Tongue depressors on sides – as feathers

In colors blue, pink, and yellow

A dead jay with scattered feathers around it

Model of the novelty object

The Owl used for experimentation Predator in the study

EXPERIMENT 1

Jay carcasses were permit-

salvagedDead jay skinNovel object14 June-15

August

EXPERIMENT 2

Presented dead jays and

great horn owl mounts

23 March – 10 June 2008

GOAL:o To compare the number of calls,

o Duration of calling, ando Effect of vocal aggregations elicited by predators and by dead conspecifics on foraging

THEREFORE:o Did not include novel object experiment

o Omitted from all analyses trials where neither calls nor aggregations occurred

EXPERIMENT 3

Recorded whether calls were elicited,

CAs occurred, peanuts were taken

or whether they portrayed

aggressive behavior

Presented the skins in established

territories during the breeding

season

21 July – 04 October 2009

EXPERIMENT 4

Observed how many Jays were attracted by the play back or did

they vocalize

1 minute play back of audio

recordings

04 – 09 September

2009

Using a Crate TX15 amplifier, one minute audio recording was played back at 12 sites at approximately 90dBF at a four meter distance with a large Larson Davis 824 sound

pressure level meter

THE RESULTS

100%

Number of callsDead Jay Novel Object

48%52%

Number of calls Dead Jay Owl

Number of nuts taken

Dead Jay Novel Object

Number of Nuts Taken

Dead Jay Owl

DISCUSSION

A dead conspecific in the absence of predator is sufficient to induce both alarm calling and subsequent risk-reducing behavioral modification in scrub-jays.

Western scrub-jays responded to a dead conspecific with loud calls near the carcass.

The play back was effective in attracting jays.

They did not react as expected to the novelty objects

The importance of Cacophonous Aggregation (as a mob) is to drive the predator away

CONCLUSION:

A dead conspecific is used as public information about risk, and that this information was actively shared with conspecifics and used to reduce exposure to risk or predators.

THANK YOU!