The Scarlet Tanager is a striking Neotropical migrant songbird, recognized for the brilliant red and black plumage of the breeding male. This species travels thousands of miles each year, moving between its summer breeding grounds in eastern North American forests and its wintering habitat in South America. The success of this long journey and the ability to raise young are tied to a highly specialized and seasonally variable diet. Understanding what these birds consume is fundamental to appreciating their ecological role.
Insects: The Staple Diet During Breeding
During the summer months, when Scarlet Tanagers are actively nesting, their diet focuses overwhelmingly on arthropods. This high-protein intake is essential for egg production, incubation, and the rapid growth of nestlings. Both parents feed the young, relying on a diverse menu of invertebrates found primarily within the dense forest canopy.
The tanager’s menu includes a wide array of insects and other small creatures, such as aphids, ants, wasps, and bees. A significant portion of their diet consists of soft-bodied larvae, with caterpillars being a particularly favored food source. The birds also consume moths, beetles, flies, cicadas, and leafhoppers, which they find among the foliage of deciduous trees.
In addition to insects, this summer diet is supplemented with terrestrial non-insect arthropods, including spiders, millipedes, snails, and earthworms. The focus on slow-moving insects and larvae ensures a steady, energy-rich supply necessary to meet the nutritional demands of a growing brood. This protein-heavy regimen supports the intense activity of the breeding season.
Fruits and Nectar: Fueling Migration
As the breeding season concludes in late summer and early fall, the Scarlet Tanager’s diet shifts from protein to high-energy carbohydrates. This change is directly linked to the need for rapid fat deposition, which fuels their extensive southbound migration. The birds seek out plant matter, specifically wild fruits and berries that offer concentrated sugars and fats.
Specific types of wild fruit become dietary staples:
- Mulberries
- Serviceberries
- Berries of sumac and elder plants
- June-berries
- Huckleberries
- Raspberries
This carbohydrate-rich diet allows them to build up the energy reserves required for their long-distance flight to South America.
While fruits are the primary focus, tanagers also consume other plant-based items. They occasionally eat tender buds and may be observed sipping tree sap or nectar. This specialized pre-migration diet prepares the tanager for the challenging journey across the Gulf of Mexico and down to their tropical wintering grounds.
How Scarlet Tanagers Forage for Food
Scarlet Tanagers employ several techniques to capture prey and gather plant material, primarily operating high in the forest canopy. Their most common method is “gleaning,” where they search deliberately among leaves and small branches, plucking stationary insects directly off the foliage. They move slowly and methodically through the dense leaves of trees like oak and maple.
The birds also engage in short, rapid flights from a perch to catch flying insects in the air, a technique called “sallying.” After snatching a moth, fly, or bee in mid-air, the tanager typically returns to the same branch to consume its meal. They can also hover momentarily in front of a leaf or flower cluster to grab an item, using fast wingbeats to maintain position.
When a tanager secures a larger insect or arthropod, it displays specific handling behavior to make the prey manageable. They often kill the item by pressing or squishing it onto a hard surface, such as a sturdy branch, before attempting to swallow it. While they prefer the high canopy, they occasionally forage on the ground or vertically on tree trunks to probe the bark for hidden food items.