In Rhode Island, spring peepers are often referred to as the "harbinger of spring" (Klemens 1993) because they generally start calling around the vernal equinox. They are one of the most prevalent frogs in the state, though the smallest (~1 inch long) that resides in southern New England. They make up for their diminutive size by emitting a high-pitched, loud, piercing call. Therefore it is their chorus that make them so apparent. Most people in Rhode Island have heard the loud vocalizations of peepers on a warm spring night in April; yet, few have ever seen a peeper because they are highly cryptic. Their body is camouflaged to resemble tree bark, where they commonly perch. In addition, they are secretive when approached, as they often remain perfectly still to avoid detection.

Males, the only ones to vocalize, produce two primary calls by expanding their throat pouch. While at breeding ponds, they emit a single, high-pitched note (i.e., resembling the call of a bird) that they repeat 15-25 times per minute. This call note is so high pitched that people often mistake this vocalization for an insect chirp and has also been likened to the ring of sleigh bells (Klemens 1993). This vocalization is intended to entice females to breeding ponds and select a particular male. (Davis 1999a). Males also utter a rapid trill when another male approaches too closely, that is apparently expressed in territorial disputes (Rosen and Lemon 1974).

Peepers are habitat generalists, ranging from mature forests to old field habitats, although they are most commonly found in or near moist deciduous woodlands. They also can be found in coniferous forests, grassy meadows, shrubby fields, gardens, sandy coastal dune habitats, as well as pine barrens (Klemens 1993). In Rhode Island, we have even seen them at the southern tip of Sachuest Point National Wildlife Refuge, where the nearest forested patch was several kilometers away (P. Paton, pers. obs.). Spring peepers in Rhode Island are found at breeding ponds from mid-March through May in Rhode Island (Paton et al. 2000, Paton and Crouch In press). The rest of year they reside away from breeding ponds where little is known about their ecology. They have been detected as far as 300 m (1,000 ft) from breeding ponds, however much more needs to be learned about dispersal distances of this secretive species (Davis 1999). Once peepers arrive on their non-breeding areas, they apparently establish territories (1-5 m [4-18 ft] diameter), generally around woody vegetation (bark debris, logs, stumps) (Delzell 1958)

Spring peeper -camouflaged

During cold winter months, they hibernate, presumably under moss or leaf litter or in shallow burrows in the soil (Davis 1999b, DeGraaf and Rudis 1983). They are able to withstand freezing of body fluids for up to two weeks (Storey and Storey 1986).

In Rhode Island, there are two times during the year when peepers are evident. March-May during the breeding season, when they are migrating to breeding ponds and during the fall (September-October) when you often hear single individuals calling from trees or bushes.

As with all other pond-breeding amphibians, peak movements take place rainy nights. In Rhode Island, adults are typically most active from 25 March to 27 May (Paton and Crouch In press). During this period, we captured 95% of adults immigrating towards breeding ponds in Rhode Island (Paton and Crouch In press). Lykens and Forester (1986) documented a similar pattern, with females arriving at breeding ponds over a 5-8 week period. Most breeding activity takes place during April, although based on captures of gravid females in May (Paton, unpubl. data) it is probable that some late females breed in ponds during May. Delzell (1958) suggested that female peepers mated quickly and left the pond within 1-2 days. After the end of May, it is very unusual to capture adults near breeding ponds, or even 125 m from breeding in forested areas (P. Paton, unpubl. data). We did not capture any adult peepers near breeding ponds in the fall, in contrast to other species such as wood frogs (Rana sylvatica)(Paton and Crouch, In press).

Metamorphs first start to emerge from breeding ponds at the end of June (~27 June). Peak emigration for metamorphs occurs around 22 July, with some individuals leaving ponds as late as 10 August (Paton and Crouch In press)

At breeding sites, males establish calling territories (Forester and Lykens 1986; Fellers 1979b) spaced about 0.5 m apart (Gerhardt et al. 1989)and occupy them for about a month (Delzell 1958). They tend to call from the ground on cold nights and from shrub or tree perches on warmer nights. Calling typically begins around dusk, with chorus volumes increasing throughout the evening; choruses can also be heard on warm afternoons. Wells and Bevier (1997) recorded peepers in Connecticut calling in air temperatures between 5-22°C and in water temperature from 10-20°C. Interestingly, there is sexual dimorphism in the hearing abilities of peepers. Studies show that females are more attuned to the frequency emitted by calling males, whereas males have difficulty hearing their own calls (Wilczynski et al. 1984). Perhaps males are just deaf from sitting in the midst of a huge chorus.

Once a pair is in amplexus, the pair will dive to the pond bottom to deposit eggs. In contrast to many anurans that oviposit eggs in communal aggregations, peepers deposit eggs singly under leaf litter or debris at the bottom of the pond (Klemens 1993). Therefore, detecting peeper eggs is extremely difficult.

In contrast to most other anurans, we have never captured individuals that were intermediate in size between metamorphs and adults; that is, juveniles; therefore, they must grow rapidly during their first fall out of the breeding ponds

Sexual maturity: Delzell (1958) and Collins (1975) reported that both sexes of peepers breed in their first year of life.

Adult peepers feed on a variety of small invertebrates, and thus, are beneficial to the environment by acting as natural pest control agents. Spiders account for the bulk of their diet (48%), although they also gorge themselves on mites, sowbugs, leafhoppers, ants, harvestmen, nematode worms, and lepidoptera (moth and butterfly) larvae (Gilhen 1984). In the spring, adults are known to eat their castoff skin (Duellman and Trueb 1986).

Recently emerged metamorphs apparently feed on spiders, ants, beetles, mites, ticks, caterpillars, and gastropods (Oplinger 1967); a diet similar to the adults.

This species presently is secure in Rhode Island. It is widely distributed across the state, including urban areas. Peepers tend to be habitat generalist, as they are found in a variety of wetlands. Gibbs (1998b) investigated the effects of habitat fragmentation on five species of amphibians and found that peepers were among the least sensitive to habitat perturbations. However, they will not breed under all conditions. Glooschenko et al. (1992) found they were sensitive to acid rain, and larva are not found in ponds with a low pH (<4.0)(Freda and Taylor 1992). In contrast, Pierce (1985) found no evidence that peeper larvae were particularly sensitive to low pH. Pesticides may impact local populations, as one population had detectable levels of DDT 26 years after the last time it has been used in the area to control mosquito populations (Russell et al. 1995).

Although they typically prefer ponds with long hydroperiods, they tend to avoid ponds with fish (Hecnar 1997), therefore fish introductions to ponds could be detrimental to local populations. However, other researchers have found that peepers can avoid vertebrate predators hiding by quietly on the bottom of the pond (Lawler 1989; Smith and Van Buskirk 1995; Skelly 1995).