Frogs in Illinois exhibit distinct periods of activity throughout the year, often referred to as “frog season,” largely dictated by environmental conditions. The timing of when these amphibians emerge, breed, and vocalize is closely tied to factors such as temperature, rainfall, and daylight. Understanding these patterns is key for nature enthusiasts and anyone interested in the state’s amphibian populations.
Annual Frog Activity Cycles in Illinois
The annual activity cycle of frogs in Illinois is influenced by changing seasons and environmental cues. As winter recedes, many species emerge from brumation, a period of reduced activity during cold months, often spent burrowed in mud or under leaf litter. Rising temperatures and increased rainfall in early spring trigger breeding, prompting males to congregate in wetlands and begin their distinctive calls. This vocalization, often referred to as chorusing, is a primary indicator of frog presence and breeding readiness.
Peak activity generally spans from early spring through late summer, with different species becoming prominent at various times. Daily rainfall, soil moisture, and air and water temperatures all play a role in initiating and sustaining these cycles. While some species have brief breeding periods, others may vocalize and reproduce over several months. The warmth and humidity of summer provide optimal conditions for continued breeding and growth.
Key Species and Their Specific Seasons
Illinois is home to a diverse array of frog species, each with its own characteristic calling and breeding period. Spring Peepers, known for their high-pitched whistles, are among the earliest to call, typically from early March to early June. Their chorus often begins in April or early May, signifying the arrival of spring. American Toads, recognizable by their musical trill, breed from March through May, with some activity extending into July, particularly after warm rains.
Green Frogs have a prolonged breeding season that extends throughout the summer, generally from April or May through September. Their banjo-like “gunk” call is a common sound around permanent water bodies. American Bullfrogs, the largest frog species in North America, have a breeding season that typically runs from late April through August. Their deep “jug-o-rum” call is a familiar sound in lakes, rivers, marshes, and ponds. Green Treefrogs, found in southern Illinois, breed from mid-May through August.
Regulations and Conservation
Illinois’ “frog season” includes legal regulations for interacting with amphibians, particularly bullfrogs. A valid sport fishing license is required to take bullfrogs. The open season for bullfrogs runs from June 15 through October 15. During this period, bullfrogs may be taken by hand, hook and line, pitchfork, spear, bow and arrow, or landing net. Firearms, air guns, gas guns, and commercial fishing nets are prohibited.
A daily catch limit of eight bullfrogs and a possession limit of sixteen apply. Bullfrogs taken by lethal methods must be kept and counted towards these limits, with no culling permitted. For other native amphibian species, a sport fishing license is generally required for collection by hand. Any collected amphibians not intended for retention must be immediately released at the site of capture.
Conservation of frog populations is important, given their role as environmental indicators. While 17 Ill. Adm. Code Part 880 details the taking of reptiles and amphibians under a sport fishing license, it is important to note that 17 Ill. Adm. Code Part 870, pertaining to aquaculture and aquatic life, specifically states it does not include amphibians or reptiles. Ethical observation practices, such as not moving frogs from one area to another and avoiding the release of non-native species, are important for protecting these sensitive creatures and their habitats.