Monarch vs Viceroy: How to Tell Them Apart

The fastest way to tell a monarch from a viceroy is to look at three things. First, check the size by comparing the wingspan. Monarchs are noticeably larger, with wingspans of 3.5 to 4 inches. Viceroys are clearly smaller, with wingspans of 2.5 to 3 inches. If you see a larger orange and black butterfly, it is almost certainly a monarch. If you see a smaller one, it is likely a viceroy. Second, look at the wing markings carefully. Look at the lower wings. On a viceroy, there is a thin black line that runs across the lower wings, cutting through the orange pattern. On a monarch, this line is absent. The lower wings are solid orange and black without this extra line. Third, observe the overall pattern. Monarchs have a more solid, symmetrical pattern. Viceroys have a slightly different pattern with the distinctive line. If you see a butterfly with an extra black line across the lower wings, you have found a viceroy. If you see a larger butterfly without this line, you have found a monarch.

Monarchs and viceroys differ notably in overall size and wingspan. Monarchs are larger butterflies, with wingspans typically between 3.5 and 4 inches. Some individuals reach slightly over 4 inches. Viceroys are considerably smaller, with wingspans typically between 2.5 and 3 inches. The size difference is consistent and reliable. A monarch's wings are also proportionally wider. Viceroys have slightly more elongated wings. Both butterflies have the same general shape, with four wings and similar body structure. The orange and black coloring on both is similar, with orange dominating the upper and lower wings and black patterns creating borders and markings. The key difference in appearance is the black line that crosses through the lower wings of the viceroy. Monarchs do not have this line. Viceroys also tend to have a slightly different pattern of black markings around the edges of their wings. The wing edges on a viceroy are more defined with black borders. Both butterflies are delicate and their wings are covered with tiny overlapping scales that create color. The structural differences between these two butterflies are subtle but the size difference is very obvious.

Monarchs and viceroys are both found throughout the United States, though they have somewhat different ranges. Monarchs are found in all US regions from coast to coast. They migrate south in fall to Mexico and Central America, then return north in spring. During migration season, you can find monarchs in nearly every habitat across the country. Monarchs pass through fields, gardens, and woodlands during their long trip. Viceroys are found in most US regions but are less common in the far West. Viceroys do not migrate. They stay in the same areas year-round. Viceroys prefer areas near willow and poplar trees, which their caterpillars eat. Both butterflies can be found in similar habitats like gardens, fields, and woodlands. The ranges overlap extensively, so you might see both species in the same location. In spring through fall, monarchs are very common in most regions. Viceroys are present year-round in areas where they live. In southern states, you can find monarchs during migration months. Throughout the US, both butterflies prefer areas with flowers for nectar and specific plants for their caterpillars. Visit your local wildlife gardens to see either species.

Monarchs and viceroys have very different life cycles and behaviors. Monarchs are famous for their incredible migration. Most monarchs live only 2 to 6 weeks. But the final generation of each year lives 8 months and flies south to Mexico for winter. This is one of nature's greatest trips. Viceroys do not migrate. They stay in the same regions year-round. Viceroys live only 2 to 6 weeks like most monarchs. The flight pattern is also different. Monarchs have a slower, more fluttering flight. They travel steadily during migration, sometimes covering 50 miles per day. Viceroys have a faster, more erratic flight. They are more agile and dart quickly between plants. Both butterflies feed on nectar from flowers. Monarchs lay eggs on milkweed plants exclusively. Viceroy caterpillars eat willow and poplar leaves. Monarchs are toxic to predators because they eat milkweed as caterpillars. The plant's toxins stay in their bodies as adults. Viceroys are also toxic but for different reasons. This mimicry of the monarch's appearance protects viceroys from predators.

If you see an orange and black butterfly and want to identify it, follow these steps. First, estimate the wingspan. Is it larger or smaller than 3.5 inches? If larger, it is probably a monarch. If smaller, it is probably a viceroy. This is your best first clue. Second, look carefully at the wing pattern if you can. Look specifically at the lower wings. Do you see a thin black line crossing through the orange area? If yes, it is a viceroy. If no, it is a monarch. Third, think about where you saw it. If you saw it in a garden with milkweed plants, it was likely a monarch. If you saw it near willow or poplar trees, it might be a viceroy. Fourth, think about the flight pattern. Did the butterfly fly slowly and steadily, or quickly and erratically? Steady flight suggests monarch. Quick darting flight suggests viceroy. Fifth, consider the time of year. In spring and fall, you are more likely to see monarchs during migration. In summer, you could see either species. By checking the size first and then looking for the extra line, you can identify the butterfly with confidence. Both are wonderful wildlife to observe.

Several myths exist about monarchs and viceroys. One myth is that viceroys are just small monarchs. This is false. Viceroys are a completely different species. The small size is consistent, and viceroys have their own life cycle separate from monarchs. Another myth is that all orange and black butterflies are monarchs. There are other species in North America with orange and black patterns. Viceroys are just the most commonly confused with monarchs. A third myth is that viceroy caterpillars eat milkweed like monarchs. This is false. Viceroy caterpillars eat willow and poplar leaves exclusively. Because they eat different plants, viceroy caterpillars cannot be mistaken for monarch caterpillars. A fourth myth is that viceroys are not toxic to predators. Actually, viceroys are toxic to many bird predators. Their toxicity comes from different sources than monarchs, but predators learn to avoid them. A final myth is that you cannot see both monarchs and viceroys in the same place at the same time. In fact, during migration season in spring and fall, both butterflies can be found in the same gardens and fields. Viceroys stay year-round while monarchs pass through twice yearly during migration.