Yes, squirrels do like sunflower seeds, and they show a strong preference for them over many other food sources. These small, agile mammals, such as the Eastern Gray Squirrel, are opportunistic omnivores with a varied diet of nuts, seeds, tree buds, fungi, and insects. They are particularly drawn to the high-energy seeds offered by humans. Sunflower seeds represent a concentrated source of calories, which is vital when preparing for colder seasons or during periods of low natural food availability.
The Strong Preference for Sunflower Seeds
A squirrel’s preference for sunflower seeds is rooted in efficient caloric return. These seeds possess a high percentage of fat, often making up over 50% of their composition, translating directly into a dense source of energy. This high-fat content is beneficial for animals that need to rapidly accumulate body fat for survival, such as before winter or for scatter-hoarding caches. The high energy content registers as a valuable prize, directly influencing the process of assessing and caching food.
Black oil sunflower seeds are especially sought after because their shells are relatively thin, requiring less energy and time for the squirrel to access the kernel inside. While squirrels also consume striped sunflower seeds, the thicker shell of this variety demands more gnawing effort, making the black oil type a more efficient choice. The combination of palatability and ease of processing allows a squirrel to rapidly ingest a significant number of calories. This preference for high-return food minimizes the time spent exposed to predators while maximizing energy intake.
Nutritional Profile and Health Concerns
Despite their desirability, an exclusive diet of sunflower seeds creates a significant nutritional imbalance for squirrels. A major concern is the extremely poor ratio of calcium to phosphorus found in the seeds. Sunflower seed kernels can have a calcium-to-phosphorus ratio as low as 1:8.5, which is far from the balanced ratio required for proper bone health. The body needs calcium and phosphorus in specific proportions, and excessive phosphorus interferes with calcium absorption, causing the body to leach calcium from its own bones.
This severe calcium deficit can lead to Metabolic Bone Disease (MBD), particularly in young, growing squirrels, resulting in skeletal deformities and fragile bones. The high fat content, while beneficial for energy reserves, can also pose problems when consumed in excess year-round, potentially leading to obesity and associated liver issues. A squirrel’s natural diet provides diverse nutrients, including minerals and protein found in fungi, buds, and insects, which mitigate these risks. Sunflower seeds function as a high-calorie treat that should only represent a small fraction of a squirrel’s total food intake, rather than a primary food source.
Behavioral Consequences of Seed Availability
The consistent availability of an easy, high-calorie food source like sunflower seeds alters the natural behavior of squirrels. When seeds are provided in predictable locations, such as bird feeders, squirrels can become habituated to human proximity, losing their innate fear. This habituation leads to bolder behavior, increasing the risk of negative human-wildlife interactions. It may also put the animals at greater risk from domestic animals or traffic.
The ease of obtaining food also reduces the need for natural foraging behaviors, such as searching for and burying diverse nuts and seeds across a wide territory. Since the food source is reliable, squirrels spend less time performing these energy-intensive activities that are important for physical and mental stimulation. Where sunflower seeds are concentrated, such as around a single feeding station, the abundance increases resource competition among squirrels. This can lead to increased territoriality and aggressive encounters as individuals compete for the most accessible food source.