Silkie the "SHH" gene, called the ZPA Regulatory Sequence (ZRS). This causes ectopic "SHH" expression in the anterior of the developing limb bud, leading to increased tissue growth and digits. While the feet of the Silkie display polydactyly, the wings have the standard tridactyly (three digit) arrangement. The Japanese Silkie initially develops additional digits in the wing as an embryo, but these are lost prior to hatching. The genetic cause behind Silkie polydactyly differs from those that cause polydactyly in the Dorking chicken breed, which is due to ectopic "FGF4" expression in the AER, with ectopic "SHH" a secondary effect. The
Bird ringing often shared throughout North American banding operations. This way information on retrapped birds is more readily available and easy to access. When deciding on bird banding equipment one must decide what species of bird they'd like to focus on. Many of the supplies used during an operation are determined by how big a bird is. The essential equipment includes a bird identification guide, mist nets, banding pliers, leg gauge, wing ruler, and a digital scale. However, before starting a bird banding operation a permit is necessary to purchase all of the equipment. This will then be taken into consideration that