Based on the results of our study, we outline management frameworks to minimise that negative impacts on New Zealand falcon productivity resulting from land
preparation (Fig. 6.2) and harvesting operations (Fig. 6.3) and at the same time create little disruption to forestry operations. In summary, falcons require a 200 m set back during land preparation until chicks are 14 days old. This set back can be reduced to 15 m after the chicks are 14 days old. During harvesting operations, a 200 m set back should be maintained early in the breeding cycle. Operations can continue with no
detail in the appendix. If pre-operation monitoring can be established, mechanical operations can be planned so as to avoid compartments containing nest sites or can be timed so as not to reach the nest area until the appropriate time, avoiding the need for these procedures.
Figure 6.2. Flow diagram illustrating a stepwise management process for land preparation operations to follow to ensure there are no negative impacts of these operations on New Zealand falcon
Figure 6.3. Flow diagram illustrating a stepwise management process for harvesting operations to follow to ensure there are no negative impacts of these operations on New Zealand falcon productivity. (See Appendix for detailed notes).
6.6 Conclusions
We conclude that the productivity of New Zealand falcons in pine forests is similar to those inhabiting other habitats in New Zealand. Predation has the greatest impact on New Zealand falcon breeding success. As a result we suggest that 1080 pest control should continue. Of the forestry management practices investigated, negative impacts were restricted to mechanical operations. We outline a management framework that if followed, will minimise these impacts and minimise disruption to forestry operations.
6.7 Acknowledgments
This research was made possible by funding from Kaingaroa Timberlands,
Timberlands Limited, Carter Holt Harvey, Hancock Forest Management Ltd., New Zealand Forest Managers and the Tertiary Education Commission in the form of an Enterprise Scholarship. We thank volunteers Mathew Clement, Shane McPherson and David Brill for their hard work in the field. We are also grateful for the contributions of the Department of Conservation New Zealand and Massey University, and advice and guidance from Wingspan Birds of Prey Trust and the Raptor Association of New Zealand.
6.8 Appendix
Additional notes to Figures 3 and 4
Characteristic New Zealand falcon alarm calls are given when the nest is approached up to 400m away, and are the first sign that can alert machine operators to a nest site (Addison et al. 2006). On approaching a falcon nest, the adult pair will begin to dive bomb the person or machine approaching. This becomes more vigorous the closer the nest is approached and the more advanced the breeding attempt is, until falcons repeatedly strike the intruder. There is variation in behaviour between pairs, and a few pairs will make very little noise and dive bomb very little, but the intensity of
aggressive calling and dive-bombing behaviour generally increases with the stage of the breeding cycle.
6.8.1 Land preparation
Our results indicated that if land preparation operations moved within 200 m of a nest scrape before chicks were 14 days old, breeding attempts had a greater chance of failure. Therefore, once nest sites are located, operations should be planned so as not to move within 200 m of the nest until chicks are at least 14 days old.
Once chicks were 14 days old or more, land preparation operations were able to move up to within 5 m of a nest with no immediate negative effect on chick survival.
However, between 30 and 40 days old, chicks are also vulnerable. At this age they begin to roam away from the nest scrape on the ground and can be up to 10 m from the nest before they are able to fly. Chicks at this stage have the tendency to freeze or hide under log piles when threatened (pers. obs.), making them difficult to observe and prone to being driven over. We therefore recommend that a 15 m undisturbed radius around each nest scrape be enforced until chicks are 40 days old and have advanced their flying skills sufficiently to avoid machinery.
If compartments cannot be surveyed for falcon breeding activity before land preparation operations begin, we suggest that operators upon spotting or hearing defensive falcon behaviour withdraw at least 200 m. If bulldozer operations in
the nest being driven over are high. Excavator operators will probably observe falcon defensive behaviour earlier than bulldozer operators, but if machine operators are not familiar with the falcons, or with the signs of their breeding, there is still a high risk of destroying nests. One of the most important factors in the whole process therefore, is that operators are well informed of how to identify New Zealand falcons and their breeding behaviour.
6.8.2 Harvesting operations
Our results also indicate that harvesting operations have the potential for the destruction and disturbance of New Zealand falcon nest sites. As with land preparation operations, if breeding behaviour is observed, harvesting operations should be moved back at least 200 m from the area until chicks are at least 14 days old. After this time, operations can continue up to within 100 m of the nest until chicks are fully fledged (40 days old) (Fox 1977). After which, operations can continue felling over the nest site. If the nest site cannot be located or the nest stage identified, then operations should stay out of the area, keeping more than 200 m away from the area in which they are dive-bombed for 45 days and 100 m away for a further 25 days.