Auxiliary Marker Info

Plastic color bands can be used as auxiliary markers to aid in identifying individual birds. Please refer to USGS Bird Banding Lab's info page if you need more information about the use of auxiliary markers here.

We offer Darvic, Celluloid, and Acetal color bands to suit your research need. Darvic is the trade name for unplasticized PVC, dyed with colorfast dyes and is UV resistant. Celluloid bands are a thermoplastic band type that have limited availability, as much of the sheet material required to make the bands is disappearing. Acetal bands are a type of acetate band that are molded on to a small card or stick, off of which individual bands are snapped off for use.

Please note that we do not recommend using color bands on bats. If placed on their forearm, the edges of color bands can tear the wing membrane and cause injuries. 

DISCLAIMER: Color bands are manufactured for application to captive and wild birds. However, as much as we wish, they are not high-tech pieces of equipment. The color of color bands may fade or shift over time given exposure to UV and the climate. Color bands may open and lose shape if kept in hot conditions such as a banding kit left in the sun or inside vehicles. Color bands can also become brittle or crack if stored for long periods in plastic containers. While color bands are extremely useful, we ask that researchers consider the limitations of this product.

What is the difference between celluloid and Darvic color bands?

Below is a sizing chart so you can find the best fit for your target bird according to their typical US band size. These are suggestions only, so if you are unsure of what will fit, it's best to purchase a stick of two sizes and see what fits best or ask a colleague. Generally, we suggest sizing up if you're unsure, but you also do not want a loose band falling over a metal band or a too-tight band causing irritation. There are outliers that we have found, for example, Red-cockaded woodpeckers get a size 1A (3.18mm) US band, and always have a size XB (4mm) color band. However, Grey catbirds wear the same size US band as RCWO and can generally wear a size XCL (3.1mm) band. 

Suggested Sizing Chart

BBL Band Size Internal Diameter Corresponding Marker Size
0A 1.98mm XF = 2.3mm 
0 2.11mm
1 2.39mm XCS = 2.8mm
1B 2.77mm
1P (Snowy Plover) 2.84mm XCL = 3.1mm
1A 3.18mm XCL = 3.1mm OR XB = 4mm
1D 3.5mm XB = 4mm
2 3.96mm XB = 4mm or X3 = 4.5mm
2A 4.2mm X3 = 4.5mm
3 4.78mm 1FB = 5.5mm
3B 5.16mm 1FB = 5.5mm
3A 5.56mm 2FB=6.4mm
4 6.35mm 2FB=6.4mm or 3FB = 8mm
4A 7.14mm 3FB = 8mm
5 7.95mm 3FB = 8mm
5A 8.74mm 4FB = 9.5mm
6 9.53mm 4FB = 9.5mm or 5FB = 11mm
7A 11.13mm 5FB=11mm or 6FB=12.7mm
7 12.7mm

6FB=12.7mm

7B 13.49mm 7FB=14mm
7D 15mm 7FB=14mm