Longtail Igloos

Bermuda Audubon Society volunteers coating styrofoam igloos

Bermuda Audubon Society volunteers coating styrofoam igloos

What are Longtail Igloos?

Longtail Igloos are artificial nests for the Longtail (or White-tailed Tropicbird). The artificial nest chambers are called ‘igloos’ because they are dome shaped and made of white styrofoam, resembling igloos. Before they can be used, entrance and ventilation holes must be cut and the styrofoam igloos must be coated to add strength and durability. The coating used is SKB roofing fiberbond mix, which is composed of fibreglass and epoxy.

Adult longtail on a nest

Adult longtail on a nest

Why are they necessary?

It has become necessary to provide artificial nesting cavities for Longtails due to the continuous loss of natural nesting places. Longtails nest in the natural holes or crevices eroded from the soft limestone of Bermuda’s coastal cliffs. These natural nest sites have been lost through coastal erosionover the last twentyyears, particularly from hurricane-associated storm surge and flooding. They have also been destroyed by human activities and development in coastal cliff areas, such as the building of docks, stairways,coastal retaining walls and other structures. Cliff holes are also often taken over by feral pigeons which make them un-usable by Longtails.

Bermuda’s population of nesting Longtails is internationally important, representing more than half of the breeding population of the species in the North Atlantic Ocean, so it is very important that they have somewhere to nest.

Where can I get an Igloo?

Longtail Igloos can be purchased by members of the public from the Bermuda Audubon Society for $75.00 (2012 price). The Society can be contacted through http://www.audubon.bm

Where should I install my Igloo?

Longtail Igloos can be installed on any piece of coastal property that has cliff or steep embankment areas more than 6 feet (1.8 m) in height, as well as tall retaining walls or terraces. Longtails have very short legs for their body size and do not walk well, so they prefer a nest site that they can fly directly into.  Therefore igloos are best situated on a flat surface on top of a coastal cliff or wall, or on a ledge on a cliff.  Be sure to place your igloo high enough up from sea level so that it will not flood in a storm or very high tide.

Consideration should also be given to the stability of the rock on which you are anchoring your igloo. If it is actively crumbling or being undercut, it would be best not to install an igloo at that location.

If you are installing an igloo on your property it would be best to think for a moment about how you and your family use the property.  Do you need regular access to the spot where your igloo will be? Will you be disturbing the birds often while they are in residence during the summer? (e.g the stairway down to your dock or beside your favourite swimming spot may not be the best place for your longtail nest). Longtails will nest near human activity, but if it can be avoided it is best for all concerned.

You should also consider whether your pets, or your neighbours pets can get access to your igloo. Dogs and cats have been known to kill nesting Longtails, so you may need to fence off your cliff topor use other means to restrict them from that area during the breeding season (from March until October).  Longtails have sharp beaks and if they feel threatened they are not afraid to use them! Make sure your kids enjoy the birds from a distance.

How do I install my Igloo?

Longtail igloo nests can be fairly easily installed in three steps:

  1. First, mark a circular outline the diameter of the igloo (about 2 feet in diameter) into the chosen location on the cliff edge, and use a hoe or mattock (pickaxe) to grade the rock into a fairly level surface that the edge of the igloo sits level on; then chop a soup-bowl shaped depression about 1 foot wide and 3 to 4 inches deep into the centre of this marked area. This nest bowl provides a secure place for the bird to nest in inside the igloo and prevents the egg from rolling out of the entrance. Mark where the entrance of the nest will be, remembering that it must face out towards the water so the birds can see it.
  2. Mix up 2 x 5 gallon buckets worth of cement (about 60 – 80 lbs.) and use the first bucket to lay down a ring of cement about 3 inches thick on the level lip around the edge of the nest depression, taking care NOT TO PUT CEMENT WHERE THE NEST ENTRANCE WILL BE or to get cement into the nest depression.  Take the igloo nest and press the nest bottom edge firmly into the cement while it is still wet, putting the entrance where the gap in the cement is.
  3. Take the rest of the cement and put some around the bottom edge of the igloo to attach it more strongly to the rock surface. The remainder of the cement can be applied by trowel over the surface of the igloo and natural weathered rocks attached, taking care not to block the ventilation hole or entrance hole. Use cement to fill in gaps between the rocks, which will make the nest look more natural and keep it cooler in the hot summer months. Two larger rocks should be cemented on each side of the entrance and a longer flat rock cemented to their tops, to create a “entrance porch” which helps to keep sun and rain out of the nest. It will also make it more difficult for predators such as crows, cats and dogs to get into the nest and kill or injure adult Longtails and their chick.
  4. The final step is to remove any rocks or bits of cement from the nest depression (inside the nest) and to put about 2 inches of beach sand to cushion the egg and prevent it from breaking.

If correctly installed, an igloo nest is quite strong and they have withstood large hurricane waves breaking over them. Remember that it may take several years for Longtails to occupy the nests, but once they do, they are likely to use them for many years.   

If you have any questions about installing your Longtail igloo you can contact the Department of Conservation Services or the Bermuda Audubon Society for assistance.

Learn more about Longtails

The White-tailed Tropicbird (Phaethon lepturus catsbyii) is known in Bermuda as the Longtail. Longtails are protected in Bermuda under the Protection of Birds Act and the Protected Species Act. This protection includes the birds themselves, their eggs and nest sites. 

Read More About Longtail Igloos