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Before using the IEC calculator, please read all instructions carefully.

Computer Requirements:
MS Excel Version:
  • Windows: MS Excel versions 5.0 (1993) or higher
  • Macintosh: MS Excel versions 11.6.6 (2004) or higher
MS Excel Solver Add-in Installation:
Windows Users:
  • MS Excel versions 2000-2003: Go to the Tools tab and select Add-Ins…. Enter a checkmark next to the Solver Add-in box in the Add-ins window and select OK. The Solver function can now be found in the Tools tab.
  • MS Excel versions 2007 & 2010: Go to Excel Options (in 2007, found by clicking on the Microsoft logo action button; in 2010, found in the File tab). Then select the tab Add-Ins on the left-side of the window. Select the Solver Add-in under the heading Inactive Application Add-ins. Then make sure that Excel Add-ins (found next to the word Manage at the bottom of the window) is selected and click Go… A small Add-Ins window will open. Enter a checkmark next to the Solver Add-in box and select OK. The Solver add-in can now be found under the tab Data and header Analysis.
Macintosh Users:
  • MS Excel version 2004: No download needed - Solver comes with MS Excel v 11.6.6. Go to the Tools tab and select Add-ins. Within the Add-ins box, enter a checkmark next to the Solver.xlam and then click OK. The Solver add-in can now be found under the tab Data.
  • MS Excel version 2008: You need MS Excel v 12.1.2 or later. Go to this link (http://www.solver.com/solver-2008-mac), download Solver. Solver must be re-opened each time you use it.
  • MS Excel version 2011: No download needed - Solver comes with MS Excel v 14.1.0. Go to the Tools tab and select Add-ins. Within the Add-ins box, enter a checkmark next to the Solver.xlam and then click OK. The Solver add-in can now be found under the tab Data.
Bird Data Requirements:

In order to use the IEC calculator, bird monitoring points must be from a northern mesic forest landscape (Curtis 1959) in parts of Bird Conservation Region (BCR) 12. In order to avoid bias, points should be positioned at least 250 m apart from each other (Howe et al. 1997). Bird data must consist of standard 10-minute unlimited-radius point counts (Howe et al. 1997; Knutson et al. 2007) collected during the breeding season (approximately late May through early July). These methods require expert bird observers* to record all birds seen or heard (including flyovers), regardless of distance to the observer, from a stationary point count location. Point counts should be conducted during the early morning hours and in good weather with minimal wind (<12 mph) and rain. Ideally, points should be located at least 100 m within a forest area.

*To ensure that high quality bird data are collected, visit the Birder Certification Online website and have your observers validate their bird identification skills.