The parrot and the string: means-end understanding in twelve psittacid bird species Krasheninnikova A.1, Bovet D.2, Busse U.1 and Péron F.2 1Biozentrum
Grindel, Dept. Biology, University of Hamburg, Germany 2 Laboratory of Compared Ethology and Cognition; Université Paris Ouest Nanterre La Défense ,France.
Introduction Parrots are known for their great cognitive skills. Tested in different physical tasks they are able to display flexible behaviours to solve novel problems. We decided to look at psittacids family bird diversity while solving folk physical problems. The ability of some bird species to pull up reward hung on a string is a famous example of spontaneous animal problem solving 1-3. The “insight” hypothesis claims that this complex behaviour is based on cognitive abilities such as mental scenario building and imagination 4. Several birds of twelve species have been tested on different string-pulling tasks, to test a) parrots’ ability to pull up a baited string (T1), b) whether pulling behaviour is goaldirected (T2), c) whether the parrots’ choice is based on the spatial or the functional relationship (T3), d) whether their strategy of problem solving is flexible or not (T4), e) bird ability for perception of connectedness (T5).
Cyanoliseus patagonus
Material & Method
Ara maracana
Amazona pretrei
Test 1: single string-pulling task Test parrots' ability to pull up a baited reward that was suspended from the horizontal perch by a single string Test 2: control task Two strings but only one baited , to bird motivations. Pulling up the string with the reward more frequently would indicate that, even if string-pulling behaviour was self-rewarding, subject could recognize the string as a means to obtain the reward. Test 3: crossed strings task Two strings crossed (coloured differently (a) or not (b)) to assess whether parrots’ choice is determined by the spatial or the functional relationship between string and reward, that is, if they pull at the string directly above the baited object as in the trials before or based their choice on the functional connection between food and string. Test 4: over-length string task The length of the string was twice longer. For some birds, it was possible to reach the reward from the ground(b). Thus the aim was to test either bird motivation and endurance (a) or bird flexibility (b). Test 5: broken strings task Only one string with a reward hung, to test if subjects are able to visually determine whether or not objects are physically connected and recognize that the string must be connected to the reward in order to work properly .
Guaruba guarouba
Rhynchopsitta pachyrhyncha Cacatua tenuirostris
Results Not all the birds were interested in the task and some of them did not interact with the string at all. We observed that some birds of all species tested succeed in all the conditions proposed. Significant differences in the time needed to solve the task as well as in the proportion of correct choices have been found across species.
T1
T3
T2
T4
T5 Melopsittacus undulatus
Tested individuals
Location LECC
Species
LECC
African grey parrot Budgerigar
FCZ
Sun parakeet
FCZ
Blue-throated Macaw
Ara glaucogularis
LP
Golden Conure
Guaruba guarouba
LPF
Blue-headed Macaw Illiger´s Macaw
Ara couloni
LPF LPF LPF LPF
LPF LPF
Psittacus erithacus Melopsittacus undulatus Aratinga solstitialis
a M; F; ParticiUnknown pated
Mean time
b
mean % of mean % of mean % of mean % of Mean time Technique* Technique Technique correct Technique correct first correct first Technique correct first (a) (b) first choice choice choice choice
1;0;0
1
10,56
F
100
F
60
40
A, F
-
F
-
-
7;6;0
5
6,65
A ,B
56
A, B, C
76
42
A, B, C
-
B, C, I
41
B, C
2;0;0
2
30,4
B, D
-
-
-
-
-
-
-
-
55
50
A, C
52,1
A
-
-
-
-
-
-
-
-
-
1;1;0
2
21,15
A, C, G
65
4;4;0
0
-
-
-
A, B, E, G -
3;3;1
0
-
-
-
-
-
-
-
-
-
-
-
Ara maracana
1;1;0
2
13,28
A, G
60
A, G
63
47
A, G
14,8
A, G
60
A, G
Thick-billed Parrot
Rhynchopsitta pachyrhyncha
4;3;0
1
29,29
A
75
A
42
57
A
20,57
A
63
A
Red-spectacled Amazon Greater Patagonian Conure Slender-billed Cockatoo Peach-faced Lovebird
Amazona pretrei
2;1;4
2
69,71
A, G, H,
85
A, G, H
25
42
A, G, H
52,77
A
66
A
3;3;1
3
21,62
A, H
56
A, H
79
69
A, H
40,3
A, H
78
A, H
1;5;0
6
11,76
A
79
A
43
53
A
33,61
A
68
A
6;6;0
6
12,08
A, G
86
G
67
72
G
10,67
A, G
75
G
Cyanoliseus patagonus bloxami Cacatua tenuirostris Agapornis roseicollis roseicollis
Agapornis roseicollis
Aratinga solstitialis
LECC – Laboratory of Compared Ethology and Cognition, Paris, France; FCZ – Ferme de Conservation Zoologique, Vierzon, France; LP – Loro Parque, Teneriffa, Spain; LPF – Loro Parque Fundación, Teneriffa, Spain A (classical) pick up with the beak, pull up, block the loop with the foot B Go down on the string C Pick up with beak and move on the side D The bird perch upside-down and pull up the string E Pick up the string with the beak and turn on itself F Pull up the string till the body is un upright position and gain more string by grabbing it with the foot G Pull up by sliding through the beak H Cutting the knot I Taking the food from the perch under the string (only possible in test 4b * going on the floor is a possibility in this situation; bold: data from a single individual: no mean calculated Technique observed:
Ara couloni
Discussion Birds display very different motor sequences in order to reach the food reward. The strategy differs across individuals and species but also across trials and tasks for a same individual illustrating their great flexibility in problem solving. Most of the birds showed a food-orientated behaviour, and it appears that different color help birds to choose the correct string. However, only some individual Greater Patagonian Conures and Peach-faced Lovebirds appear to understand the functional relationship between string and reward and to percept connectedness between objects.
Psittacus erithacus Acknowledgments: INCORE (Integrating Cooperation Across Europe) financial support Loro Parque & Loro Parque Fundacion , Teneriffa, Spain Contact:
[email protected],
[email protected] References: 1Werdenich & Huber 2006, 2Schuck-Paim et al. 2009, 3Krasheninnikova & Wanker 2010, 4Taylor et al. 2010
