A ruler or a measuring tape can be used to measure the length of a leaf. Simply lay the leaf flat on a surface and measure from the base of the leaf to the tip.
The biggest hawk in the world is the Ferruginous Hawk (Buteo regalis), with a wingspan of about 4.5 to 5.5 feet (137 to 168 cm) and a length of around 22 to 27 inches (56 to 69 cm). They are native to North America and are known for their large size and powerful flight.
You can buy a 50mm diameter MS pipe with a 1-meter length from hardware stores, construction supply shops, or online retailers that specialize in selling construction materials. Make sure to specify the exact dimensions and material type when making your purchase to ensure you get the right product.