Blue tit (IMAGE) University of the Basque Country Caption More than 5,800 observations on the colouring and other characteristics of the blue tits like this one were made between 2005 and 2019 Credit David López-Idiáquez. Usage Restrictions Credit must be given to the creator. Only noncommercial uses of the work are permitted. Adaptations must be shared under the same terms. License CC BY-NC-SA Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.