Low Level Road Project – Mitigation Measures – Bald Eagle Habitat
Thursday, January 31 2013 @ 04:01 PM EST
Contributed by: davidh
Port Metro Vancouver
100 The Pointe, 999 Canada Place
Vancouver, BC Canada V6C 3T4
direct: 604.665.9244 mobile: 604.753.9906
Report on the Low Level Road Project Regarding Bald Eagle Nest Mitigation Jan 30, 2013
As a long time advocate for bald eagles I was at first sad to learn that the 5 year efforts of a bald eagle pair to establish, while unsuccessfully, a nest on the Port Metro Vancouver property in North Vancouver was coming to an end. Then I learned that a permit to remove this nest had been given by the Ministry of Environment, but that there was a possible positive upside for eagles. MOE was demanding mitigation, and this mitigation was being very positively viewed by Port Metro Vancouver.
I have had to stand by over the years and idly watch eagle nests come down and no mitigation had been forthcoming. The fact that mitigation is happening I am now so pleased to be able to “stand in for the eagles” and offer suggestions as to what they need in return. This cooperative project between the MOE, PMV and private consultation is a positive landmark project. That the eagles will gain far more than they are losing is a tribute to the cooperative effort of the MOE and Port Metro Vancouver.
Thank you for giving me this opportunity to speak for the eagles. I look forward to completing the artificial nest installations.
Enclosed are my final proposals and recommendations on what can be done along the North Shore to positively mitigate the loss of the Esplanade bald eagle nest.
Bald Eagle Biologist
Hancock Wildlife Foundation
19313 Zero Avenue, Surrey BC
V3S 9R9 604 -761-1025
Low Level Road Project – Mitigation Measures – Bald Eagle Habitat
The Low Level Road Project is part of a broader investment and improvement strategy on behalf of the Government of Canada, Province of British Columbia, Port Metro Vancouver, TransLink, the City and District of North Vancouver and the private sector. The strategy is designed to facilitate projected port-related growth to meet international trade demands while maximizing benefits and minimizing impacts on local communities.
As a primary east-west route for the North Shore, the importance of the Low Level Road has long been reflected in community and transportation plans. Upgrades on this road are required to improve safety and better accommodate the needs of all users including cyclists and pedestrians. The project is important to Port Metro Vancouver because it provides for more efficient operations for tenants and provides community benefits for the City of North Vancouver. These benefits include minimizing noise impacts from Port operations, a permanent solution to unstable cut slopes above the existing road and completion of the Spirit Trail between St. Georges Avenue and Kennard Avenue.
Key elements of the project include:
• Re-alignment of the Low Level Road to the north
• Providing space for two new rail tracks to improve rail efficiencies
• Eliminating three existing at-grade rail crossings
• Providing intersection and road safety improvements between the Esplanade/Low Level Road intersection, and the East 3rd Street/ Cotton Drive/Low Level Road intersection
• Addressing slope stability along the Moodyville bluff
• Addressing long-standing safety, recreation and noise challenges associated with Port operations along the existing Low Level Road
• Completing the Spirit Trail and providing upgraded cycling and pedestrian facilities.
Background on Eagles
The eagle is one of nature’s most impressive birds of prey. Males generally measure 3 feet from head to tail, weigh 6 to 8 pounds, and have a wingspan of 5.5 to 6.5 feet. Females are larger, some reaching 14 pounds with a wingspan of up to 7 feet.
Eagles are opportunistic predators. They feed primarily on fish, but also eat a variety of waterfowl and other birds, small mammals, and turtles, when these foods are readily available. Carrion is also common in the diet, particularly in younger birds. Small road killed mammals and feral pigeons, first killed by peregrines, are prime food source for nesting eagles. Bottom-dwelling fish tend to occur more frequently in the diet. Eagles capture fish by extending their talons a few inches below the water's surface. Therefore, live fish are vulnerable only when near the surface or in shallows.
Eagles nest from October to July. Nests are constructed primarily by the female, with the male assisting. The typical nest is constructed of large sticks, with softer materials such as leaves, grass, and Spanish moss used as nest lining. Nests are typically used for a number of years, with the birds adding nest material every year. Eagles often have one or more alternative nests within their territories. Eagle nests are generally found from 15 to 36 meters (50 to 120 feet) above the ground, in a tall, sturdy tree but in recent years nest regularly on man-made structures.
It takes at least two weeks for a pair of eagles to build their nest. A typical bald eagle nest (eyrie) will range from 1.2 to 2.5 meters (4-8 feet) in diameter and about 0.8 to 2 meters (2 to 6 feet) high. The nest cavity, where the eggs are laid, will be about 30 to 40 centimeters (12 to 16 inches) in diameter and about 10 centimeters (4 inches) deep.
Peak egg-laying occurs in March and April, with hatching primarily in April and May. The female lays a clutch of 1 to 3 eggs, but the usual clutch is 2 eggs. A second clutch may be laid if the first is lost early in incubation. Incubation begins when the first egg is laid and usually lasts 34 to 36 days. The young generally fledge (fly from the nest) in 12 weeks, but the adults continue to protect them for another 1 to 2 weeks while in the nest territory when the young are abandoned. When they are on their own, young eagles migrate, returning to the region in October or November after feasting on the spawned salmon to the north.
It has been stated for many years that an eagle pair will mate for life, but if one partner dies, or disappears, the other will generally find another mate. A newly bonded pair may work several years on a nest before actually breeding but frequently nest successfully the first year. They may desert one nest site and start again somewhere else within the territory; this usually extends about 1 to 2 kilometers (1/2 to 1.25 mile) along the shoreline. In food rich flood plains or farmland crossed with ditches and lots of food , the eagles can nest less than 0.5 kilometer apart.
An eagle will return to defend the nest territory in October and then put more effort into the nest rebuilding in January and February. Each nesting pair will spend a great amount of time preparing the nest before any egg is laid. The successful nest is generally located in a large tree very close to water, either the sea, a lake or river, where adequate food is available. Eagles are believed to live up to 30 years or more in the wild.
Threats and Reasons for Decline
Habitat loss over the past 200 years is the factor most consistently associated with declines in eagle populations. Unfortunately for eagles, people also like to live and spend their leisure time near water. In recent decades, the accelerated pace of development along the coast and near inland rivers and waterways is a primary cause of habitat loss, particularly the loss of trees capable of supporting a large eagle nest.
Human disturbance can also be a cause of population decline. Activities such as logging, construction, and recreational activity certainly do disturb eagles in some instances. However, the impact of these disturbances is highly variable, depending on the activity, its frequency and duration, its proximity to areas used by eagles, the extent to which the activity modifies the habitat or its use, and timing in relation to the reproductive cycle. Also, some birds are more tolerant of disturbance than others, with adults generally less tolerant than immature birds. Despite this variability, disturbance near nests has caused nesting failures.
In the past another key factor in the decline of eagles was human attitudes. Most predators were considered ‘vermin’ and shot. The State of Alaska even offered a bounty for killing eagles.
Finally, the most dramatic declines in eastern eagle populations resulted from environmental contaminants. Beginning in 1947, reproductive success in many areas of the country declined sharply, and remained at very low levels through the early 1970's. After several years of study, the low reproduction of eagles and many other birds was linked to widespread use of the insecticides DDT and Dieldren. These insecticides were used extensively in agriculture and forestry beginning in 1947. As DDT entered watersheds, it became part of the aquatic food chain, and was stored as DDE in the fatty tissue of fish and waterfowl. As eagles and other birds of prey fed on these animals, they accumulated DDE in their systems.
Although occasionally causing death, DDE mainly affected reproduction. Some birds affected by the chemicals failed to lay eggs, and many produced thin eggshells that broke during incubation. Eggs that did not break were often addled or contained dead embryos, and the young that hatched often died. Since the ban of DDT and DDE residues in Bald Eagle eggshells have dropped significantly, and a slow recovery of eagle productivity has occurred. Today most eagle populations appear to be producing chicks at the expected rate.
Of more recent concern is evidence that lead poisoning may be a significant cause of death in eagles. Chronic low levels of lead can produce nervous system disorders, affect behavior and learning, cause anemia, and increase susceptibility to disease. As laws requiring the use of steel shot to hunt waterfowl become effective, accumulation of lead in the food chain is expected to decline. Electrocution and hits by vehicles as the eagles scavenge road kills collectively kill the most eagles.
The greatest challenge for the future will be to prevent further destruction of habitat and retention of sufficient creek and river flows to support a food base for breeding and wintering eagles. Monitoring of nesting success is particularly important in detecting any problems associated with contaminants in the environment. In the urban and suburban regions the loss of nesting trees is paramount. However, just as eagles have adapted to finding good food sources in and around cities, they have also adapted to nesting on artificial structures. Finally, appropriate management of nesting, feeding, loafing, and wintering habitat must be a priority if we are to maintain the current upward trend in eagle numbers. The recent trend of eagles to accept artificial structures for nesting gives some hope for them to reoccupy areas that have suffered major tree losses.
Tolerance to Disturbance
Eagles fear humans at all times, but will tolerate less disturbance during the nesting season, than at other times of the year. A nesting pair will seek isolation, and any human interference, if prolonged, may drive the birds away from the nest.
During the winter, eagles will roost and feed in groups close to human habitation and activity. However, prolonged and repeated disturbances will send the birds on their way in search of another isolated roost or feeding area. Extensive disturbance at these feeding and roosting sites can lessen the eagles’ survival chances as secondary roosts if available, will in all probability not have the vital weather protection that the primary roost provided. Eagles generally choose to roost in large trees in protected places within a few miles of their feeding grounds. Along the river, for example, they most often roost in heavily wooded, steep-sided valleys, sheltered from northerly winds, or in cottonwoods on islands away from human disturbance.
Eagles, being large birds, need large strong trees for nesting, roosting, and perching while hunting. Most coniferous trees have to be over 100 years old and cottonwoods over 50 years old before they can be used as nesting sites for the eagle. Logging and subdivision operations have disturbed or destroyed many nesting territories and potential nest sites, as well as winter roosts.
Disturbance at or near the actual nest site up the tree is particularly disruptive. Some eagles have accommodated very effectively in the urban and suburban environment to human activities below a nest. Most eagles nesting within the Metro Vancouver area nest in parks, golf courses or isolated remnant trees throughout the city where the eagles have learned people are not harmful. This accommodation can take eagles a few years. In a number of cases the eagles have sufficiently accommodated to the good city food supply that they have nested in artificial structures when no suitable trees were available. The higher the nest up the tree the less important seems the disturbance below the tree.
Nest Choice and Disturbance
Intensive recreational or industrial use of land near nests and roosts can disturb the birds. As the human population expands and moves in greater numbers back into the countryside, the eagle is pushed back into smaller and smaller pockets of suitable habitat. Fortunately for humans, eagles are attempting to adjust to our urbanized ways.
The critical point to remember is that eagles are very territorial birds, and most breeding pairs return to the same nest site year after year. In areas of great food availability eagles can nest within 250 meters of each other or spread out along a shoreline about 1 to 3 kilometers apart where the resources are fewer. They may use the same nest annually for as many as 35 years, or they may build additional nests in their nesting territory, and alternate the use of them from year to year. If their nests are disturbed or destroyed, the pair may never re-nest again in that tree. The challenge then for the territorial pair is to find another structural support within their territory that will support a nest, so although there are large tracts of wild land away from water available to eagles, the territorial nature of the birds, their precise feeding and nesting requirements, and their past nesting habits, limit the number of suitable nest sites.
Known Eagle Pairs in Project Area
The Project extent overlaps the territory of at least two known eagle pairs, both of which have nests close to or within the project limits. The first of these pairs is located adjacent to East Esplanade on a strip of Port owned land on the south side of Esplanade. As shown in Figures 1 & 2, for the purpose of this report these will be referred to as the “Esplanade Eagles”.
Figure 1 – Project Extents
Figure 2 – Project East End ‘Esplanade Eagles’
The second pair is located in Moodyville Park on the north side of the existing Low Level Road, as indicated in Figures 1 & 3, and for the purposes of this report these will be referred to as the “Moodyville Eagles”. This pair has available several large old Douglas Firs suitable of supporting a nest. In fact, the nest presently being worked on by them is in a tree adjacent to the tree they previously nested in, according to local eagle authority David Cook. Both the old and new tree appear to be different than the first tree they were observed nesting in about 15 years ago.
Figure 3 – Middle of Project – ‘Moodyville Eagles’
Esplanade Eagles Background
The Esplanade pair has attempted, so far unsuccessfully, to nest in two local sites that we know of. The first attempt was about 5 or 6 years ago when the territorial pair started to build a nest on one of the nearby steel cranes, a short distance from the Esplanade nest. This had somehow been destroyed or fell from the structure. Then 3 years ago they started to build the existing nest in the Cottonwood tree on the Esplanade. This nest is still not complete nor very well structurally supported, from the perspective of an Eagle observer the tree could be considered a last resort, with very little alternative nesting habitat elsewhere in the area.
The Esplanade eagles have been observed in the area since fall of 2011 when they constructed the nest in the Cottonwood tree. At the time the nest was constructed there was a significant amount of activity but in early 2012 there were some heavy/strong winds, which reportedly damaged the nest. In October 2012, the beginning of the 2013 nesting season, the pair returned to the area and have been observed perching in the Cottonwood tree. The pair regularly occupies the docks, boats, derricks and cranes as territory hunting perches.
Both David Cook and David Hancock have examined the nest from the ground and consider it to be in poor condition and precariously placed on branches that are not-very-sturdy.
The Project covers an area which provides good feeding habitat for eagles, as is demonstrated by the two pairs which have territory in the area. Spilled grain from the railcars which service the grain terminals, is a food source for small mammals and birds which supplement fish from the Burrard Inlet as food sources for the eagles. The mature and tall trees near the Moodyville nest territory, and tall Port buildings and cranes in the Esplanade nest territory provide excellent and multiple perching locations which help the eagles while hunting for food and during feeding.
Historical records show that the Burrard Inlet and the area now occupied by the Port was once densely vegetated with mature trees, which provided excellent habitat for eagles to perch and hunt for food, and in which to nest and rear young. During the development and urbanization of the surrounding area most of the trees adjacent to the prime water feeding areas were removed, which reduced the available nesting habitat for eagles.
Two mitigation options could be applied in the area of the Project which would encourage eagles into the area. Within the Port lands, there are wide open spaces where no trees currently exist. The installation of an artificial nest would provide eagles with a perch for feeding or nesting. Although this does not replace the trees which would have existed many years ago, it could encourage eagles back into the area. Plantings around an artificial pole and nest would offer some additional habitat for other species. Artificial poles as nest supports are frequently used by eagles in this region.
Some examples of artificial nest/perches are shown below:
Away from Port lands the other mitigation measure is to improve existing habitat. Typically this would involve the removal of some of the upper limbs of trees to create an open area and encourage a nest to be built. The felled limbs could also be placed to create a platform that would provide an improved nesting location. Many trees have had limbs removed and supplemental branches added to facilitate eagles building their own nest.
A review of the North Shore Trade Area and surrounding lands provided two possible locations suitable for artificial nest/pole/perch installation and two sites where habitat improvements could be made. Figure 4 provides details of these locations. These sites will significantly benefit eagles in the area by providing a suitable nesting site.
Figure 4 – Mitigation Extents
Artificial Nest Site 1
The first artificial nest site is on the foreshore adjacent to the existing Esplanade nest on the road to the Richardson Grain Terminal and is very close to the Low Level Road Project area. On the south side of the pole would be the shoreline. This site is nearly equidistance from the existing Esplanade nest and the earlier crane nest, but closer to the water. Figure 5 shows the location of the first artificial nest site. This location would be a possible alternative site for the existing Esplanade eagles, providing easier access to the water and the eagles main food source fish, as well as small mammals and birds which feed on any spilled grain. It is recommended that the pole at this location be 75 feet tall.
The territorial pair occupying the Esplanade area have already attempted to nest on such an artificial structure; one of the large cranes. This proposed mitigation site would be a natural selection for them, even putting them closer to their food supply and farther away from possible human disturbance.
Figure 5 – Artificial Nest Site 1
This site is also on the south side of the port security fencing preventing disturbance from the general public. Yet at the same time the nest would be very visible from the Spirit Trail passing to the north.
Artificial Nest Site 2
The second location is at Beech Yard, which is east of the Low Level Road Project area and to the north east of the Second Narrows Crossing Rail Bridge. Figure 6 shows the location of artificial nest site 2. This location is outside of the immediate project vicinity but would encourage a new pair of eagles to move into the local area. At the moment this foreshore area is prime eagle foraging habitat but it does not contain any suitable nest trees. This location is both to the east of the Lynn Creek eagles territory (on the west side of the Second Narrows Crossing Rail Bridge) and west of the Maple Flats eagles, the next active eagle territory to the east. The proposed site is sufficient distance so as not to likely interfere with these existing pairs and allow another additional pair to establish a territory in an area that currently has no adequate large trees for nesting.
Figure 6 – Artificial Nest Site 2
Tree Modification Opportunities
In addition to the two possible nest/poles mitigation works there are two locations further to the east also outside of the project area, where habitat improvements could be made to encourage eagles into the area. The first is within the Tsleil-Waututh Nation Reserve and opportunities are subject to discussions with the Nation. There are a number of mature trees within the reserve where pruning of upper limbs would make the trees more attractive for eagles to nest. Specific trees have not yet been identified and additional site visits will be required before the exact details can be confirmed. Figure 7 shows the first area where habitat improvements could be made.
Figure 7 – Habitat Improvement Area 1
The second site is Cates Park, this site is similar to the Tsleil-Waututh Nation site as there are a large number of mature trees on the east end of the park where pruning and removal of some upper limbs could encourage eagles to nest. Again specific details would require additional site visits which would be undertaken as a second stage to the installation of the posts and artificial nests. Figure 8 shows the second area where habitat improvements could be made.
Figure 8 - Habitat Improvement Site 2- Cates Park
Consideration of Area West of the Esplanade Bald Eagle Territory.
At present a well-established pair occupies Mahon Park and hunts the Mosquito Creek Basin and the adjacent waterfront to the immediate west of the Esplanade territory. While land at the waterfront has been suggested as a possible site it does not seem valid to try and squeeze another pair into this Mosquito Creek coastal region at this time.
Below are details of the Project timelines and estimated dates by which mitigation measures may be put in place.
• May 2012 - MFLNRO contacted and permit application submitted
• June 2012 - CNV give approval for Project
• December 2012 - Funding agreements signed
• December 2012 - CNV Project Agreement signed and design approved
• January 2013 - MFLNRO issue permit for tree removal
• January 2013 - Tree removal planned
• February/March 2013 - Mitigation to be installed
Submitted on behalf of bald eagles.
Bald Eagle Biologist
Hancock Wildlife Foundation
19313 Zero Avenue
Surrey BC, V3S 9R9
An article by David L Cook (Spring, 2008) “Past, Present and Future Bald Eagle Nest Sites on the North Shore of Burrard Inlet” provides background on the eagles in the area; it also provides an overview of the bald eagle nests on the North Shore.**