Roosting (management)

Roosting habitat

A range of areas in a site will be used by shorebirds for roosting depending on several factors, including the height of the high tide and prevailing weather conditions. Sites can also be used differently at night compared to daylight hours. Shorebirds need to be secure from predators while roosting and the sites will often be at least partially isolated by water (islands, peninsulas) and/or have good visibility away from tall trees where birds of prey can seek cover.

The best roost sites have little or no disturbance, are close to feeding sites and have particular physical characteristics that encourage their use by shorebirds. Different shorebird species have different preferences for the surface of the roost. This can range from sandy to rocky, from salt marsh to old growth mangroves, and from wet to dry. The usual locations for roost sites are on low estuarine islands, along undisturbed shorelines or open peninsulas, or on the open flats behind the shoreline. Several species of migratory shorebird primarily roost in mangrove trees, e.g. grey-tailed tattler, whimbrel and terek sandpiper in Shoalwater Bay. It is likely that mangrove roosts across northern Australia are under-documented.

Roost sites can be easiest to survey at high tide, except when access to parts of the wetland is difficult. In these cases, aerial survey can be helpful and can enable a large number of roosts and/or an extensive shorebird area to be surveyed on the same day while the tide is at optimal or near-optimal height. Sites can vary greatly in extent and some of the best sites offer roosting opportunities on both neap and spring high tides. Such sites may also be of use at midtide heights when birds will collect briefly before moving out to feed at low tide.

General management principles include:

• identify and map roost sites within the wetland complex
• understand the pattern of usage of roost sites and the feeding areas they serve
• protect roost sites from avoidable disturbance and direct loss, e.g. foreshore development
• provide buffer zones of at least 100 m where possible from noise and movement by people
• provide physical barriers if there is obvious threat from predators, such as foxes or dogs
• avoid indirect changes to roosting habitat, e.g. draining of salt marsh, chemical contamination, growth of mangroves across vital shoreline roost sites
• maintain old growth mangroves as tree roosts for species such as tattlers and whimbrels.

Habitat renewal

Roosting sites are often lost to development or suffers from heavy disturbance, whereas feeding sites may be less affected by coastal development because they are situated in the intertidal zone. Therefore, the restoration of roost sites can enhance the usage of coastal areas by shorebirds. Existing roost sites may be re-designed, enhanced or entirely artificial roost sites established.

There are good examples of successful artificial roost sites in south east Queensland and elsewhere where features that are typical of natural roost sites are incorporated into the design. Design considerations include:

• proximity to feeding areas
• protection from disturbance
• protection from prevailing winds
• slope and access to nearby natural shoreline
• minimum effective size
• the nature of the substrate and vegetation both near and close to the site
• elevation and nature of tidal flows across the site
• protection from erosion
• likely long-term maintenance requirements.

Additional information

• Shorebird locations in Queensland
• Coastal high-tide shorebird habitat management guidelines

Last updated: 28 September 2021