Notes about the DUCK file extension:
Incorrect file associations could be the result of underlying issues within your PC system. As such it is highly recommended to scan your PC for invalid registry entries, unused processes and other unfavourable system settings to identify slowdown issues.
The DUCK file type is primarily associated with 'Cyberduck' by David V. Kocher. Cyberduck is an open source FTP, SFTP, WebDAV and Amazon S3 browser licensed under the GPL with an easy to use interface, integration with external editors and support for many Mac OS X system technologies such as Spotlight, Bonjour, Quick Look and the Keychain. This file is similar to a PLIST file and contains the various information necessary for an FTP connection.