In the 1990s, the plight of grassland birds received increased attention (Johnson and Schwartz 1993, Knopf 1994, Johnson and Igl 1995), as researchers began to recognize that grassland species were showing “steeper, more consistent, and more geographically wide-spread declines than any other behavioral or ecological guild” of North American birds (Knopf 1994:251). Many grassland passerine populations had been declining for decades (Peterjohn and Sauer 1993, Herkert 1995, Igl and Johnson 1997), and it was thought that high rates of nest predation could be contributing to these declines (Basore et al. 1986, Martin 1993). At that time, there were few data...

Many bird species have suffered loss, degradation, and fragmentation of the habitats on which they depend (e.g., Askins et al. 2007). As a result, conservation efforts on behalf of these birds have largely focused on habitat manipulations or restoration. However, population status of birds is not totally determined by habitat factors. One particularly important aspect of avian ecology is productivity, and nest predation can be a large source of nesting mortality, especially for passerines (Ricklefs 1969; Martin 1988, 1995; Newton 1998; Thompson 2007). Not knowing who the nest predators actually are can affect not only our understanding of the ecology...

Cameras, most recently video surveillance systems, have been employed to document nesting activities of many types of avian species including songbirds and some gamebirds. Before such camera systems were available, monitoring avian nesting behavior relied primarily on direct observation, a daunting task that was time consuming and logistically challenging (Weller and Derkson 1972). For example, identifying nest predators depended on examining remains at the nest, which could be ambiguous and misleading (e.g., Thompson et al. 1999, Pietz and Granfors 2000). For gamebirds, cameras have been used to study nesting behavior, time budgets associated with reproduction, breeding strategies such as nest...

Over 100 years ago, Leon J. Cole presented a report on tagging wild birds in which he suggested that “premature fledging” (Smith 2010:469) was probably the greatest danger to young birds from the work of banders. Banders during that period had discovered that older nestlings sometimes “could not be induced to remain in the nest after they had been removed in the process of banding” and that “in several instances banded young were later found dead near the nest” (Cole 1910:166). Although recognizing that these deaths were not necessarily a result of banding activities, Cole “called on banders to report...

Biologists have linked nest attendance to nest predation risk (reviewed by Lima 2009). Duncan Rastogi et al. (2006) reported that songbirds with greater nest attendance tended to have lower rates of daytime predation. Recent application of nonlinear models to examine effects of nest age on survival has provided evidence of varying predation risk during the nest cycle (Grant et al. 2005, Kerns et al. 2010, Post van der Burg et al. 2010). Giovanni (2009) reported lower survival immediately following hatch and during the nestling period for Western Meadowlarks (Sturnella neglecta) on our study site. Although biologists suggest that feeding activities...

Environmental and temporal factors can influence incubation attentiveness, the amount of time parents allocate to incubating their clutch. Time of day may influence incubation attentiveness via changes in ambient temperature, prey activity, and predation risk (Holmes et al. 1978, Morton and Pereyra 1985, Conway and Martin 2000). Understanding incubation patterns not only provides insight into the proximate and ultimate factors influencing this life history trait, but is also necessary to facilitate research that depends upon finding an adequate number of nests (Gloutney et al. 1993). Grassland songbirds are of high conservation concern (Brennan and Kevlesky 2005), and a number of...

Parental investment during nesting involves a number of physiological and behavioral parameters that influence the likelihood that offspring will survive. Incubation entails protection of eggs during development, most commonly thought of as warming the embryos to proper temperature for development, but might also include cooling of eggs and protection of eggs from predators. Many ground-nesting species of Galliformes, including the Northern Bobwhite (Colinus virginianus; hereafter, bobwhite), are difficult to observe; therefore, most observations of incubation behavior are individual and anecdotal (Stoddard 1931). Because of the well-documented bobwhite decline (Church et al. 1993, Brennan 1999), a great deal of research has...

Although birds inhabit nearly every corner of the globe, the range of environmental conditions that ensure the hatching of their eggs is quite narrow. The optimal temperature for embryonic development, for example, ranges from only 36 to 38°C across a wide variety of species (Lundy 1969, Drent 1975, Webb 1987). Consequently, birds have evolved behavioral traits to warm or cool the nest, as their environment dictates. For shorebirds breeding in the Arctic, significant energy must be expended to maintain eggs within an optimal range when ambient temperatures are well below it (Piersma et al. 2003). To limit the energy required...

Information on the behavioral ecology of breeding passerines (e.g., Poole 2005) is biased toward activities that occur during the daylight hours. Even early studies that used sensors in nests had this bias; for example, a study by Weeden (1966) was conducted at a latitude seasonally lacking darkness and Kendeigh (1952) focused on measurements made during the day. The paucity of information available on nocturnal behavior of nesting passerines may reflect logistical constraints of working in the dark as well as a lack of appreciation for the existence or relevance of nighttime activity. Video surveillance systems remove the logistical constraints and...

As a result of widespread and steep population declines, many grassland bird species are now of conservation concern at both state and federal levels (Askins et al. 2007). Alteration and loss of habitat (including fragmentation) are considered to be among the most important factors in these population declines (Brennan and Kuvlesky 2005, Askins et al. 2007). Grassland birds have faced wholesale changes in habitat since settlement of North America by Europeans. For example, native tallgrass prairie has been reduced to a fraction of its historical acreage in the U.S. (Samson et al. 1998). More recently, the amount of nonnative grasslands...

Predation is often the leading cause of nest failure for passerines (Newton 1998, Thompson 2007). High predation rates can limit productivity of a population and have been implicated as a possible source of declining songbird populations (Brawn and Robinson 1996, Newton 2004, Adams et al. 2007, Thompson 2007). Despite substantial efforts to correlate predation rates to habitat and landscape features, few general trends have emerged, and most are related to temporal factors or nest stage. Study conclusions are conflicting and often study-site or regionally specific (Thompson 2007, Lahti 2009), causing some to speculate that nest predation is random or unpredictable...

Variation in avian responses to predation, with adaptive responses in nest placement, clutch size, sociality/coloniality, and feeding behavior, across both species and broader taxonomic units, demonstrates that nest predation is an important force in avian evolution (e.g., Ricklefs 1969, Martin 1995, Hansell 2000). Parental nest defense often entails dramatic behaviors that have captured the interest of behaviorists and the general public. The distraction display of a Killdeer (Charadrius vociferous; Brunton 1986), the hiss of a titmouse (Baeolophusspp.) or chickadee (Poecilespp.) (Grubb 1998), and the heightened aggression of Red-winged Blackbirds (Agelaius phoenicus; Knight and Temple 1988) and Northern Mockingbirds...

In many birds, especially ground-nesting species, predation is the leading cause of nest failure. Not all nest predation events, however, lead to the complete loss of the nest. Partial depredations occur when a predator chooses (e.g., predator is satiated) or is forced (e.g., nest defended by the attending bird) to consume only part of the clutch of eggs, thus leaving some eggs intact with the potential to successfully hatch (Ackerman I et al. 2003a). Partial depredations have been documented and occur frequently in several waterfowl species (Choate 1967, Lariviere and Messier 1997, Ackerman et al. 2003a). Partial clutch loss in...

Grassland species experience higher rates of nest predation than birds nesting in forest and wetland habitats (Martin 1993). Although nest success can be highly variable, some studies show predation rates for grassland songbird nests to be as high as 50–70% (Winter 1999 , Davis and Sealy 2000). Predation is often the primary cause of nest failure (Davis 2003, Jones et al. 2010). Understanding factors driving spatial and temporal variation in nest survival requires that we identify nest predators and factors influencing predator abundance and behavior. Such information may allow land managers to prescribe appropriate land use and management regimes...

In 1956, Gysel and Davis presented an “automatic photographic unit for wildlife research,” which they baited with dove eggs to identify potential predators. Three years later, Royama (1959) published the specifications for an “auto- cinematic food-recorder” which automatically triggered photographs of prey in the bills of Great Tits (Parus major) each time they perched on a trigger mechanism at the entrance of their nest-box. In the subsequent 50 years, ornithologists have employed photo and video technology to study birds at their nests with increasing frequency. Such technology allows for the collection of data that would otherwise be impractical to obtain...