New Caledonian crows attend to multiple functional properties of complex tools.

Area of Science:

• Animal behavior and cognition
• Evolutionary biology
• Primate tool use

Background:

• Tool use is crucial for foraging efficiency and fitness in many species.
• New Caledonian crows (Corvus moneduloides) exhibit sophisticated tool use, employing stick and pandanus leaf tools.
• Previous studies showed crows failed to orient pandanus tools functionally, a puzzling observation given fitness benefits.

Purpose of the Study:

• To investigate if New Caledonian crows discriminate functional properties of hooked stick tools.
• To determine if crows can orient hooked stick tools correctly, irrespective of presentation.
• To explore which tool features influence orientation decisions in 'unnatural' tool configurations.

Main Methods:

• Experimental presentation of naturalistic replica hooked stick tools in various orientations to New Caledonian crows.
• Assessment of tool orientation during foraging tasks.
• Companion experiment using 'unnatural' tools with reversed functional features (hook, curvature, bark stripping) to test feature salience.

Main Results:

• All crows successfully oriented hooked stick tools correctly, regardless of initial presentation.
• Crows attended to multiple tool features (hook, curvature, bark stripping) when making orientation decisions.
• The location of the terminal hook was the most critical feature for tool orientation.

Conclusions:

• New Caledonian crows demonstrate a capacity to attend to and utilize functional tool properties, specifically with hooked stick tools.
• This contrasts with previous findings regarding pandanus tools, suggesting context or tool type may influence discrimination.
• Further research is needed to understand the flexibility and constraints in crow tool-use strategies.