Geology topics

Daniel E. Clark

Publications and source records attributed to Daniel E. Clark.

5 recordsLinked to original sources

USGS2016

Roost site selection by ring-billed and herring gulls

Gulls ( Larus spp.) commonly roost in large numbers on inland and coastal waters, yet there is little information on how or where gulls choose sites for roosting. Roost site selection can lead to water quality degradation or aviation hazards when roosts are formed on water supply reservoirs or are close to airports. Harassment programs are frequently initiated to move or relocate roosting gulls but often have mixed results because gulls are reluctant to leave or keep returning. As such, knowledge of gull roost site selection and roosting ecology has applied and ecological importance. We used satellite telemetry and an information-theoretic approach to model seasonal roost selection of ring-billed ( L. delawarensis ) and herring gulls ( L. argentatus ) in Massachusetts, USA. Our results indicated that ring-billed gulls preferred freshwater roosts and will use a variety of rivers, lakes, and reservoirs. Herring gulls regularly roosted on fresh water but used salt water roosts more often than ring-billed gulls and also roosted on a variety of land habitats. Roost modeling showed that herring and ring-billed gulls selected inland fresh water roosts based on size of the water body and proximity to their last daytime location; they selected the largest roost closest to where they ended the day. Management strategies to reduce or eliminate roosting gulls could identify and try to eliminate other habitat variables (e.g., close-by foraging sites) that are attracting gulls before attempting to relocate or redistribute (e.g., through hazing programs) roosting birds.

Massachusetts↗

USGS2016

Fidelity and persistence of Ring-billed ( Larus delawarensis ) and Herring ( Larus argentatus ) gulls to wintering sites

While the breeding ecology of gulls (Laridae) has been well studied, their movements and spatial organization during the non-breeding season is poorly understood. The seasonal movements, winter-site fidelity, and site persistence of Ring-billed ( Larus delawarensis ) and Herring ( L. argentatus ) gulls to wintering areas were studied from 2008–2012. Satellite transmitters were deployed on Ring-billed Gulls ( n = 21) and Herring Gulls ( n = 14). Ten Ring-billed and six Herring gulls were tracked over multiple winters and > 300 wing-tagged Ring-billed Gulls were followed to determine winter-site fidelity and persistence. Home range overlap for individuals between years ranged between 0–1.0 (95% minimum convex polygon) and 0.31–0.79 (kernel utilization distributions). Ringbilled and Herring gulls remained at local wintering sites during the non-breeding season from 20–167 days and 74–161 days, respectively. The probability of a tagged Ring-billed Gull returning to the same site in subsequent winters was high; conversely, there was a low probability of a Ring-billed Gull returning to a different site. Ring-billed and Herring gulls exhibited high winter-site fidelity, but exhibited variable site persistence during the winter season, leading to a high probability of encountering the same individuals in subsequent winters.

Waterbirds↗

USGS2015

Assessing gull abundance and food availability in urban parking lots

Feeding birds is a common activity throughout the world; yet, little is known about the extent of feeding gulls in urban areas. We monitored 8 parking lots in central Massachusetts, USA, during the fall and winter of 2011 to 2013 in 4 monitoring sessions to document the number of gulls present, the frequency of human–gull feeding interactions, and the effectiveness of signage and direct interaction in reducing human-provisioned food. Parking lots were divided between “education” and “no-education” lots. In education lots, we erected signs about problems caused when people feed birds and also asked people to stop feeding birds. We did not erect signs or ask people to stop feeding birds at no-education lots. We spent >1,200 hours in parking lots (range = 136 to 200 hours per parking lot), and gulls were counted every 20 minutes. We conducted >4,000 counts, and ring-billed gulls ( Lorus delawarensis ) accounted for 98% of all gulls. Our educational efforts were minimally effective. There were fewer feedings ( P = 0.01) in education lots during one of the monitoring sessions but significantly more gulls ( P = 0.008) in education lots during 2 monitoring sessions. While there was a marginal decrease ( P = 0.055) in the number of feedings after no-education lots were transformed into education lots, there was no difference in gull numbers in these lots ( P = 0.16). Education appears to have some influence in reducing the number of people feeding gulls, but our efforts were not able to reduce the number of human feeders or the amount of food enough to influence the number of gulls using parking lots.

Massachusetts↗

USGS2014

A versatile technique for capturing urban gulls during winter

The capture of birds is a common part of many avian studies but often requires large investments of time and resources. We developed a novel technique for capturing gulls during the non-breeding season using a net launcher that was effective and efficient. The technique can be used in a variety of habitats and situations, including urban areas. Using this technique, we captured 1,326 gulls in 125 capture events from 2008 to 2012 in Massachusetts, USA. On average, 10 ring-billed gulls ( Larus delawarensis ; range = 1–37) were captured per trapping event. Capture rate (the number of birds captured per trapping event) was influenced by the type of bait used and also the time of the year (greatest in autumn, lowest in winter). Our capture technique could be adapted to catch a variety of urban or suburban birds and mammals that are attracted to bait.

Massachusetts↗

USGS2013

Stainless-steel wires exclude gulls from a wastewater treatment plant

There is growing concern about the prevalence of pathogens and antibiotic-resistant bacteria in the environment and the role wildlife plays in their transmission and dissemination. Gulls feeding at wastewater treatment plants may provide a route for transmission of pathogens and bacteria to public water supplies or other critical areas. The authors identified gulls routinely feeding at a wastewater treatment plant in Millbury, Mass., and tested the effectiveness of overhead stainless-steel wires in excluding gulls from the plant. The number of gulls in certainstructures was compared before and after wiring and during an experimental approach using simultaneous treatments and controls. Stainless-steel wires spaced at 0.9-3.3 m (3-10 ft) effectively prevented gulls from using treatment structures (p < 0.0001) and were effective for > 24 months. Materials costs to wire all structures was about $5,700, and labor costs were $4,020. Overhead stainless-steel wires can provide a long-term, cost-efficient method of excluding ring-billed gulls from wastewater treatment plants.

Massachusetts↗