Q31 - Mapping Bulbul Territory Size from Playback Response Data

Theoretical A Real exam question - full text reproduced under IBO's CC BY-NC-SA 4.0 license

Aggression, Territoriality & Social Structure

The territorial behavior of the red-whiskered bulbul (Pycnonotus jocosus) was studied during pre-nesting and nesting periods. Songs of decoys were played from ten different locations around a farmhouse, where the test birds lived, and the time taken to start displaying territorial behavior by the resident male was measured at the different locations (Table Q.31). The resident bird defended the territory with aggressive calls, threat display and tried to attack the decoy.

Station	C	I	K	G	H	B	F	J	D	E
Distance (m)	20	50	110	30	50	19	46	72	29	38
Direction	N	N	N	S	S	E	E	E	W	W
Pre-nesting: Territory defense	+	+	-	+	-	+	+	-	+	-
Pre-nesting: Response time (min)	1	3	>10	5	>10	1	3	>10	4	>10
Nesting: Territory defense	+	+	-	+	-	+	+	-	+	-
Nesting: Response time (min)	0.2	1	>10	0.7	>10	0.3	2.5	>10	1	>10

Using the information and data, determine which of the statements are true or which are false.

A. The territory size during the pre-nesting period was smaller than that during the nesting period.

B. The quadrangle made by stations G, D, I and F marks the territory size of the bird.

C. The male responded more rapidly to the decoy within its territory during the nesting period.

D. The intensity of territorial behavior displayed is a dependent on seasonal fluctuation of hormones.

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Question reproduced from IBO 2016, Theoretical Paper A, licensed under CC BY-NC-SA 4.0 - attributed to the International Biology Olympiad. Open the full exam PDF · Community solutions (unofficial)