In socially monogamous species, low availability of sexually active unpaired individuals in the local population may constrain mate choice, resulting in mating with sub-optimal partners. Here we experimentally investigate whether female reproductive behaviour is different when paired with a preferred or a non-preferred male in the zebra finch (Taeniopygia guttata). First, we assessed female mating preferences using a four-way choice apparatus, then females were caged together with either their preferred or least-preferred male. Female reproductive motivation, assessed by the propensity of laying eggs within two weeks from pairing and clutch mass, did not differ between the two experimental groups. Females responded to mate removal by either increasing their care, so as to compensate for the lost care of their mate, or by significantly reducing incubation. This bimodal response was not explained by mate preference, nevertheless, we found that females with lower baseline (i.e., pre-manipulation) incubation effort were more likely to cease incubation during mate removal. Taken together, we found no evidence that female reproductive behaviour varies along with mate preference.

Consistent individual behavioural differences ('animal personalities') are documented across a variety of animal taxa. Sexual selection, especially assortative mating has been suggested as a possible mechanism contributing to the maintenance of different personality types within populations but little is known about non-random pair-formation with respect to personality traits in unconstrained choice tests. We here tested whether female mating preferences were non-random with respect to male and female neophobia in zebra finches (Taeniopygia guttata), an important avian model of mate choice and animal personality research. Male and female neophobia was assessed by attaching novel objects to birds' feeders. Females' mating preferences were tested with randomly assigned, unfamiliar males in a four-way choice apparatus. Females associated most with males with neophobia scores similar to their own. These results provide evidence that mating preferences and personality traits can covary, supporting evolutionary scenarios of assortative mating contributing to the maintenance of personality traits.

Automated behavioural observations are routinely used in many fields of biology, including ethology, behavioural ecology and physiology. When preferences for certain resources are investigated, the focus is often on simple response variables, such as duration and frequency of visits to choice chambers. Here we present an automated motion detector system that use passive infrared sensors to eliminate many drawbacks of currently existing methods. Signals from the sensors are processed by a custom-built interface, and after unnecessary data is filtered by a computer software, the total time and frequency of the subject's visits to each of the choice chambers are calculated. We validate the detector system by monitoring (using the system) and in the same time video recording mating preferences of zebra finches in a four-way choice apparatus. Manual scoring of the video recordings showed very high consistency with data from the detector system both for time and for frequency of visits. Furthermore, the validation revealed that if we used micro-switches or light barriers, the most commonly applied automatic detection techniques, this would have resulted in approximately 22% less information compared to our lossless system. The system provides a low-cost alternative for monitoring animal movements, and we discuss its further applicability.